Just an update on some added information for all you guys. I still hadn't found my definite answer as to the differences are between the E90/92 vs E82 coilovers on the KW/SpeedTech [made by KW, essentially same as V1] brand. So I decided to shoot an email to the company directly.
What I had sent:
I'm looking for a set of coilovers for my BMW 2008 135i. I was wondering what the differences are between the E82 (135i) spec V1/V2's & the Speedtech ST Coilovers are verses the E90/92 (335i) spec V1/V2's & ST's.
I know that in terms of bolting up to the chassis they are exactly alike, and I should have no problems with installing either in my 135i.
But my question lies with what's different between the 135i & 335i V1/V2/ST's.
Are the struts themselves exactly alike, but with a slightly higher spring rate? That's my best guess, and what people on forums have said.
But I'm after a definitive answer before choosing a set that I'd like.
Specifically, if the spring rates are the only thing that's different between 135i/335i Coilovers. Then could you possibly provide me the specifics as to what the spring rates are at.
& the response I got back:
Thank you for contacting KW Suspension, the difference between the 135i and 335i coilover kits are going to be the rear dampers. Both kits use progressive or variable rate springs which we do not rate because technically you will never know what rate the spring is at while driving because the vehicle height is infinitely changing. With that said I would also recommend running our Variant 2 system specific to your 135i that is height and rebound adjustable, the housings are stainless steel and will not corrode, they also come with a limited lifetime warranty in the event that you ever have any issues. I have included the part number and MSRP $ below.
Variant 2- 15220039 MSRP $1949.99
I also looked at the KW site and noticed the height drop with the E90/92 & E82 were different.
KW Coilover Kit V2
KW Coilover Kit V2 BMW 1series E87 Learn More
Part #: 15220039
Front Lowering: 1.4" to 2.5"
Rear Lowering: 1.4" to 2.1"
KW Coilover Kit V2
KW Coilover Kit V2 BMW 3series E90 Learn More
Part #: 15220032
Front Lowering: 1.2" to 2.3"
Rear Lowering: 0.9" to 2.1"