Bilstein B4

[Wistfullyod]

I bought these from RockAuto: BILSTEIN 22112811/BILSTEIN 22112880 and I'm curious to see if anyone else has tried them on their MS3. I used these to replace worn stock suspension. Major differences were in the overall extended strut length (difference was about 2 1/2" - 3" I believe) and brake line brackets (which were too small but were easily modified to work.) Other than that these fit nicely. So far it rides pretty well, but to be honest I haven't driven a stock car with good suspension to compare it.

[tegxsi]

Those are part numbers are not for Mazdaspeed. Bilstein made B6 and B8 are for Mazdaspeed.
You don't want struts/shocks that are longer since MS3 sits a little lower than base model 3s.

[MSMS3]

B4 is intended to be an OEM standard shock/strut with soft valuing and dampening. Even if it is the correct length, it’s not intended for our cars. The part numbers are for normally aspirated standard Mazda 3 and certain Volvo’s. They are likely longer, as our cars sit lower than the regular Mazda 3. They may bottom out under full compression.

B6 is the proper high performance Sport strut and shock for use with OEM Mazdaspeed 3 springs. It has the famous firm but compliant action you want for improved handling without sacrificing daily driving refinement. It is an excellent improvement over our OEM struts and shocks.

B8 has exactly the same valving and dampening as the B6, but has a 1/2” shorter shaft to use with lowered suspensions.

Our cars need the correct model specific B6 or B8. Installing B4s would be a step backward.

[Wistfullyod]

Thanks for the insight. I'm planning on switching over to B8's or some FSD's in the future. I threw these on here because I just finished an engine an tranny rebuild and I was bit strapped for cash and wanted to be able to use the car. Just wanted to see if anyone else had risked trying these. To be honest I haven't had any issues with the B4's bottoming out but I also did trim the new bumpstops. The only thing that I have noticed is that they feel a bit underdamped when pushed hard but for the price I really can't complain. I guess only time will tell how long they last anyway.

[tegxsi]

B4's are probably aren't bad and they do carry a lifetime warranty. Factory shocks/struts felt nice when the car was new. When I got to about 40k the car started to feel floaty. I just recently went with Bilstein B14 coilovers. They are a bit stiffer than I expected but I like them.

[MSMS3]

Originally Posted by tegxsi B4's are probably aren't bad and they do carry a lifetime warranty. Factory shocks/struts felt nice when the car was new. When I got to about 40k the car started to feel floaty. I just recently went with Bilstein B14 coilovers. They are a bit stiffer than I expected but I like them.

The shafts are longer because regular Mazda 3s sit higher. They will probably bottom out on full compression. That might damage shock mounts and strut bearings. And they are softer. But driven easy, they might do until he can save up for B6 (MS3 height) or B8 (MS3 on lowered suspension).