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      12-23-2016, 11:53 PM   #1
GMSZ4M
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Need suspension recommendations

Hi Guys,

Thanks in advance for your help.

Last time I brought my 2006 Z4MC with 52K miles for wheel alignment, I was told one of the front struts was bent, which was causing the alignment to be off by 0.5 degrees

My ride has been pretty bumpy as well. I am planning on bringing it in for Inspection 2 to a local independent well reputed BMW service center, and wanted to club the suspension work with it.

I'm not very well versed with technical talk, and want to make sure I'm able to articulate the work I'm looking to have done, without being talked into stuff I may not need.

Here are my questions:
  1. What would be a good replacement suspension? I've read Koni are great; if so can you please point me to make/model?
  2. Is there a full kit or do I have to order parts separately?
  3. Should I switch out both front and back?
  4. Should I order them myself and bring them in with me, or have the shop order them

Other info. that may be pertinent - I haven't tracked the car but may do so in the future.
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      12-24-2016, 10:04 AM   #2
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This a very rough guide on when to replace struts/shocks, but typical half life is about 30K miles. What that means is that at 30K miles they've lost roughly half their damping capability, at 60K miles another half of the remainder (1/4 of original damping), at 90K miles another half of the remainder (1/8 of original damping), etc. You're at a mileage where you'd be considering replacement regardless of the supposedly bent strut.
The first question that needs to be answered is what do you really plan to do with the car? You indicate you might do some track days but if you're not serious about that you don't need to spend the extra $$ for higher performance dampers. If it's really just going to be street driving then the Bilstein B6 would be a good choice. If you're really going to autocross or occasionally track the car then you might want to step up to dampers which have adjustable damping and then there more decisions to be made.
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      12-24-2016, 03:18 PM   #3
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Hi dc_wright,

Thanks for your recommendation. Yes, it will primarily used for street driving. I could move forward with the Bilstein B6 per your recommendation.

With that said, can you please help me understand the following:
  1. Is there a full kit or do I have to order parts separately? If latter what are those?
  2. Should I switch out both front and back? (Sounds like a yes, based on the normal wear and tear)
  3. Should I order them myself and bring them in with me, or have the shop order them
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      12-24-2016, 03:49 PM   #4
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Quote:
Originally Posted by GMSZ4M View Post
Hi dc_wright,

Thanks for your recommendation. Yes, it will primarily used for street driving. I could move forward with the Bilstein B6 per your recommendation.

With that said, can you please help me understand the following:
  1. Is there a full kit or do I have to order parts separately? If latter what are those?
  2. Should I switch out both front and back? (Sounds like a yes, based on the normal wear and tear)
  3. Should I order them myself and bring them in with me, or have the shop order them
1. If you are replacing just the struts/shocks they're ordered individually. If you're doing springs and shocks they typically come as a kit. If you click on the Bilstein B6 link in my previous post it will take you to the Bilstein site where you can get the part numbers.

2. Yes, you're at the mileage to do both front and rear.

3. You need to consult with the shop. Many shops will not install parts brought in by the customer.
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      12-24-2016, 07:31 PM   #5
GMSZ4M
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Thanks, this helps a lot.
  • The B6 kit (without the springs) cost $650
  • The B12 kit (with the springs) cost $900
Couple follow up questions:
  1. What will the B12 get me over B6? Better ride, longevity?
  2. Is it recommended to switch out springs as well? If so, the B12 kit turns out equal, if not cheaper, to B6 and Springs purchased separately.
I don't mind putting in the extra money for the B12 if the benefits justifies the cost.
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      12-24-2016, 08:36 PM   #6
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You don't need to replace your original springs unless they're corroded or one of the coils is fractured or broken. The Eibach Pro Kit springs in the B12 kit will lower the car about 1.5" and the ride will be a bit firmer. Some would say too firm, others say they're fine.
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      12-25-2016, 12:01 AM   #7
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Thanks, much appreciated.
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      12-30-2016, 02:26 PM   #8
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Hi,

I talked to the shop and they quoted me $1560 for front, and $700 for rear (parts & labor included).

The price quote above includes struts, bump stops, and mounts. Here's their approx. price breakdown:

Front
  1. Struts - $300 x 2
  2. Bumps - $27 x 2
  3. Mounts - $135 x 2
  4. Labor - $400

There was quite a bit of disconnect where it came to pricing on parts, so I pointed them to ECS Tuning website for pricing, but they said they couldn't match them.

They are open to me bringing in the parts (only caveat is they can't guarantee the parts), so looking for all the parts I can order online to save some costs.

Also, I was led to believe that Mounts must be changed at the time of installing new shocks/struts. Wanted to get a second opinion.

Thanks!
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