What modifications would I do over? <now back to stock> Long Post

[Burt Reynolds]

I am preparing my beloved 2007 M Coupe to be sold. It has been a great car and I have had fun modding it over the 18 months I have owned it. In the end, I have decided this car which was both daily commuter and fun car did not quite fit my needs. As such, I have returned my core to bone stock and thought I might share my (non-expert) user experience and thoughts about what the modifications did and did not do.

I have been through newness of several of these mods and tried to talk myself into seeing big gains in some places. Now that I have lived with the mods for a while and taken them back off, I can give a little more objective feedback on what I experienced. I am not passing this off as expert opinion, jut my opinion so feel free to ignore this post if I am saying something you don’t like:

1.Tires- Stock Contis Stink. I should not have waited 3 months to ditch these and pick up some decent summer tires.

2.Suspension- I opted for the KWV3. After living with several modifications, I really felt like I was more confident driving the car with these coilovers and a good alignment. This would be one of the first things I did if I were starting over…by a mile.

3.4.10- LSD. I really loved what gears did for this car. My only advice is to get DINAN 3.91 or some other dif with a warranty. They do grenade as several people including myself have experienced and it gets expensive quick without a warranty. Don’t go cheap unless you can do the work yourself or are comfortable with the risk.

4.Headers- This is an easy big bump in low end torque and hp. This made about as much of an appreciable jump in power as my differential swap. I might get headers and leave the rest of the exhaust stock unless you wanted the rumble as I did. Aftermarket headers with an otherwise stock exhaust might make a nice sleeper car.

5.Exhaust- I really don’t believe any of the cans or x-pipes will make the car appreciably faster. If you buy one, pick the one with the tone you like the best b/c I honestly feel that is what you are buying. Headers made a big difference to the power. The rest of the exhaust is simply for sonic pleasure. I would buy Supersprint all over again b/c I love the sound. I think it made a little power up top but who knows. With the headers, it was no question.

6.ESS Tune- Made the car more drivable. Throttle response in non-sport mode is much better. As far as power, I am not sure but it seemed to help midrange torques with my aftermarket X-Pipe. In summary, I would buy it again but primarily for the drivability characteristics that it offers and not necessarily power. If you ever felt you wanted a throttle response somewhere between stock and sport mode, the ESS tune is worth considering.

7.Wheels- I had superlight/expensive forged wheels that looked great on my car. They were a cosmetic addition more than anything so this mod sits down at the bottom of my performance list. If I were doing a looks list, it would be at the top under my suspension. I saved 14lbs per corner of rotational mass so I thought I would comment on this mod as a performance mod too.

8.Stubby Antenna- looks good but radio reception is diminished. If you don’t get great radio reception to begin with, might reconsider.

9.RPI Scoop- Skip the scoop. It might have added power but my idle was a little rough even with a tune. Also, if it added power I would have to see it on a dyno because I could not tell that much on the butt dyno. There was a time where I tried to talk myself into the added HP at 70mph stick but if I am honest with myself, I just don’t see it.

999.Dice Ipod adapter- plain and simple never worked the way it was supposed to.

Hope that helps some prospective modders.

[Dammmittt]

Thanks for sharing Burt. Hope you enjoy your next addition to the stable.

[nmulax]

So what's the replacement going to be?

[Starscream]

Originally Posted by nmulax

So what's the replacement going to be?

+1

(and where are the mod parts for sale)

[Nate2046]

Thanks, that's a good summary for most of the mods people tend to consider. Nice to have that perspective from someone who lived with them for some miles.

[Burt Reynolds]

Not really sure but I know that trying to mix a commuter with my fun car is not wise as the conditions hear salt/snow would be harsh over time. I will probably end up with an AWD SUV as my commuter and then take a little time to pick out a fun car that spends most of its time at the track. Decisions-

Yes I will be selling all the parts ultimately....

[crfine88]

Good Call,

No since in dragging the M through salt/snow. All that wear and tare would be hard to live with.

Good luck with sale/ sales on car and parts.

[M_Six]

Have you offered the car for sale with all the mods in place?

[Burt Reynolds]

No...probably will trade since I own the car to get the tax credit towards next purchase. Will do better with the 10% sales tax savings towards next car vs. trying to get an additional 10% out of the sale of my car....especially in the winter.

[fatmatt0116]

I can relate to your predicament. Wouldn't have bought the M without my intangibly valuable rusted out pathfinder to spare it from the elements.

On another note, how many miles can one expect to get out of a set of coil overs? Is it worth buying a used set?

[Burt Reynolds]

I have had coilovers on my last 5 cars and never saw any of them fail. My guess, and only a guess, is about the same a stock. The caveat would be that road conditions are the same. Nice thing about KWV3s is that they have stainless steel dampers so they are imprevious to the elements unlike Konis. Maybe someone here will have more info...my feedback is just based on my own personal experience.

[Rick Hunter]

Will be sad to see your M go. You've had a wonderful time with your mods and I've had just as much fun following your threads.

Good Luck with your next ride!

[thekurgan]

Burt, are you saying the scoop can affect the idle? I did read a SIB for the Z4M that mentioned modifications to the intake and the idle quality, but thought it was more geared towards removing the charcoal filter.

[9.RPI Scoop- Skip the scoop. It might have added power but my idle was a little rough even with a tune. Also, if it added power I would have to see it on a dyno because I could not tell that much on the butt dyno. There was a time where I tried to talk myself into the added HP at 70mph stick but if I am honest with myself, I just don’t see it.]

[Starscream]

I have the Rpi scoop with a ESS tune and no problems with idle,

Even before the tune never had a problem,
I also am feeling the tune waking the car up the more I drive, Ive done 70 miles since getting the DME back and I swear the car is feeling stronger everytime I take it out,

[Burt Reynolds]

I closed up scoop, put back in paper filter and charcoal filter and rough idle went away. I do know that the Scoop made no appreciable power that I could feel. You might be able to see a couple ponies on the dyno but I sure could not feel it. I would rather put that 200.00 for filter and scoop towards decent tires or some other mod that really matters. YMMV.

[thekurgan]

Thanks, Burt, I also believe the scoop without any tune makes little difference and is oversold.

[skim]

nice write up.. thanks for it
do you have a picture of your car with all these mods on? just curious how your pride and joy once looked.

[AWM3]

When it's time to move on, it's time. Good luck with your new auto adventure. I've felt pretty much the same way about most of the cars I've had. Enjoyed them and then got something different with no regrets. I haven't felt that way about the E86 because I don't think there will be any more BMWs like it for a long time to come, if ever. Plus the fact that they were the last US made BMW sports cars. There are a lot of great cars on the market, but either they're mass produced and generic, or very expensive. For the price of a nice used Z4M, you could get perhaps a new GTI for example, a 200 HP 4 cylinder front wheel drive car based on an econobox chassis. I prefer to keep the Z4M and use something else for daily commuting. It's the only car I've ever had that my wife and kids have specifically said not to get rid of, and my kids are negotiating over who gets it when I can't drive it any more.

[BMWI6]

I call dibs on the exhaust please!!!!! when and for how much are you selling it????? Il pay paypal immediately

[Starscream]

I also would add the 4.10 gears and ESS tune make a great difference to the car,

The Rpi scoop, ehh, debatable,
I'm glad I got mine at a good price used,

I would also LOVE to do headers but NJ is strict on emissions and getting around passing inspection is a problem for me,

"If" you have the ESS tune accommodate the headers by turning off the CEL for the 02 sensors you will never be able to pass emissions from any state that used OBDII testing,
The DME will always come back "not ready"
So I'll miss out on the 20 or so BHP the headers gain simply because of this,
I think that will also affect re-sale as the next owner wouldn't be able to pass and thats just a headache for me,

So keeping it street legal the ESS tune works wonders with the 4.10 gears

[Z4MCJJ]

Burt, It'll be sad to have you leave our very small community....I modded my car about the same time or just after you did....several of your posts were very helpful to me.

I stopped using my M Coupe as my DD shortly after I started modding it....I have an E class I use as a DD....but I just purchased a track dedicated car. I found the M Coupe to be very expensive to maintain as a track car. Plus I was always mindful that I'd be out $50K if I ever put it into the wall. I will still use the M occasionally for track duty as it is a very fun and fast car on the track. Good luck with your next purchase.

[DarkstarZero]

What are your thoughts on the OEM Strut Tower Brace? Worth the $300?
How did you get around emissions testing with the headers? Is it worth getting something like the active autowerke/supersprint headers over $100 ebay headers?

As for the RPI scoop; I have it paired with the GruppeM intake and after installing the scoop it felt like the engine was breathing a little bit better at speed. Also had a slightly better throttle response. But those differences were very small.

So... want to trade diffs?