[The HACK]

There are 4 tiers of suspension products for the BMW market.

The upper echelon, the pro-sumer level, consumer brands, and the budget product. I can best relate this with photography equipment.

On the top end, you have the brands like Leica and Hasselblad. These are medium to large format sensors. Some are worth as much as a used luxury car. They serve a single purpose only most of the time, and have a very niche appeal. But there's no disputing that they make the BEST equipment in the world.

On the pro-sumer side, you have the Canon and Nikon DSLRs. They do what they do fantastically well, and even have a few markets cornered. They're far more versatile, relatively affordable, but still require a fair investment. Lots of aftermarket support for these, like flashes, filters, triggers, ring lights, etc. You can do a lot, and the upper end of their product range can even compete and rival with the upper echelon photography equipment.

Then on the consumer side, you have the likes of Sony and Olympus and Panasonic. Now, don't get me wrong. They have a lot of photography products that are fantastic. Sony's mirrorless digital cameras are even considered solid competitors to the pro-sumer grade Nikon and Canon DSLRs. But at this point you're buying from companies that don't really concentrate on making only cameras. You're buying from companies that makes printers. TVs. Speakers. Medical equipment. So on and so forth. And again, don't get me wrong. Even Nikon and Canon makes products in this range to compete.

And then you have your budget stuff. Cameras that are basically disposable from brands you've never heard of. Like a Seuny. Or Yonglong. Or Digigear. On paper the product reads fantastic, like 200,000 megapixel, 1 Mil X digital zoom, shoot up to 20,000 shots without recharging, build in 5 billion lumen flash...etc. The cost to replace the battery and for the price of a new high speed UHDSDXCWXYZ card is higher than the camera itself, but anyone will tell you that photography is all about the framing of subject and controlling of light, so in the hands of a world class photographer the images still turns out as stunning as something shot with a Hasselblad.

If you're not a camera buff, there's probably a similar analogy in there for just about any market there is. Bicycles. Jetskies. Cars. Computer cases. Laptops. Et cetera, et cetera.

But back to suspensions for BMWs.

The top end stuff, are most likely going to be Öhlins, JRZ, MCS, Motons. There's a couple of smaller, one-off brands built by a small handful of elves that does fantastic work on track that can't seem to scale to a larger sales capacity. These are typically favored by racers with big budget, they don't tend to function exceptionally well for street, but there are exceptions (Öhlin's ROAD and track kit works well on street). Typically they specializes in building fantastic dampers with voodoo/magic based valving that does sh*t to your car's weight transfer like you wouldn't believe.

Then just below that you have a few brands like Hanchey, AST, and TC Kline that are just full of people who know their sh*t when it comes to tuning a suspension, and built excellent products that won't cost you the price of your car and a left testicle for something that works 99% of the time to get you well within 1/100th of a second to the guys on the leaderboard with unlimited budget. Their top end, three way adjustable with nitrogen remote reservoir shocks are just as good, sometimes better, than the bottom end bump and rebound adjustable shocks from the likes of Öhlin, JRZ, Moton, etc. These will also typically include some of the ancillaries that are required to install your suspension, like shock-mounts, camber plates, and god forbid, SPRINGS that goes with the coil over.

After that, you have a very crowded consumer field, with a wide range of quality and offering. Again, in this bracket, you have companies like GroundControl, KW, Bilstein, H&R, Eibach, Koni, and a few that I probably have let slip my mind and if any of my buddies are reading this, will likely give me sh*t over the next time I see them, all competing for the largest slice of the pie. Unlike the upper echelon companies, these guys make suspension for EVERYONE. From simple springs, or simple shock and spring set, all the way up to racing kits with fully 3 way adjustable remote reservoir stuff. And their top end stuff is quite good, and can be expensive, but you'll always run across racers that run MCS or Motons that piss you off, because you know you're probably just as good a driver, but they almost always seem to be about 2/10th of a second a lap faster than you. You'd want to blame the equipment, but you really can't.

Then the rest of the field is populated by smaller players, budget brands, or companies that are well known with OTHER marques that are constantly trying to fight for the bottom half of the cost to value market. These guys don't necessarily have bad products, it's just that they're either unknown within the community, or source their products from a third party and rebrand, or reuse parts bin products to save cost, or heck, have to compete with more features for less buck just because they're small. ANYONE will tell you that a great driver can drive on these budget suspensions just as fast as you can drive with a set of JRZs on your car, but that doesn't mean they're as good.

Having said all that.

It doesn't mean that, say, a KW Clubsport isn't as good as whatever AST makes. Or a GC kit isn't as premium as a JRZ. There's a lot of product cross over, and in the end of the day, you get what you paid for, and you have to truly do your due diligence and understand that you ARE paying for what you need, but not paying for what you want. So for a guy who's looking to convert a stripped race car in Modified class for BMW CCA CR, getting a set of Megan Racing rebound adjustable coil-over is going to get him NOWHERE (on the podium, or near it. I mean, he'll still be able to go SOMEWHERE). Or a guy just looking to cruise the blvd., with stretched tires on 22s, occasionally "carving" some mountain roads? MCS 3 way with Swift Springs and remote reservoir isn't going to do him (or her) any more good than that same Megan Racing coil-over IMO.

But I'm sure you know all that. So I'm going to tell you this. I've had GC's Track School kit on my MZ4 Coupe. I liked it. A lot. But now that I'm riding on KW Clubsports I can tell you that the GC kit has some quality issues and they couldn't get the rear dampers quite right. I don't have JRZs on my MZ4 Coupe, but have driven and ridden with a few friends who have them on their BMW CCA CR cars, and JRZ is LEGIT, especially on track. You pay more for the premium dampers, but you get every cent you put in back in the quality and amount of control you have in your chassis. Every. Single. Cent.

But I wouldn't tolerate that E36 with JRZ that I drove back from Laguna Seca on a daily basis. No way. Especially not when you have to rebuild it annually since driving it on street basically destroys the valving. Since you said the Z4M Coupe is going to be primarily be used for track, I would think the JRZ would be a better choice than the GroundControl. Unless you're working with Jay personally to have a race only kit build using customized 3 way Remote Konis and Swift/Hyperco/Whatever float your boat springs, then at that point it's a toss up, because I have met Jay and seen him give seminars on suspension tuning, dude knows what he's talking about.

But I digress.