Hey all, my first post here.
I picked up a 2010 128i a couple weeks back with the sport option and just started working on it. First upgrade I did was replacing the stock sport suspension with the ///M Performance suspension with springs.
I am a dealer tech and picked up everything at work. I haven't found too much out about the kit, trying to find out more and share what I've found.
The kit I purchased was 33500444831 with 31336788891 (T1) front springs and 33536788898 (T1) rear springs. According to BMW, the new setup will lower the vehicle by 10mm compared to the sport suspension and 25mm compared to standard vehicles. The spring rate is 34% stiffer than the sport setup and 48% stiffer than standard. Spring travel is 26.5mm front axle, 12mm rear axle.
I went through some technical date from AIR this week and here's a chart for 2010 models except 135is. I specify because I didn't go through every years data to compare. Ride height is measured from the bottom of the wheel to the wheel arch.
Series Standard Suspension
Front- 16"- 579mm, 17"- 595mm, 18"- 607mm
Rear- 16"- 572mm, 17"- 587mm, 18"- 599mm
Sport Suspension
Front- 16"- 564mm, 17"- 580mm, 18"- 592mm
Rear- 16"- 556mm, 17"- 572mm, 18"- 584mm
///M Performance Suspension
Front- 16"-554mm, 17"-570mm, 18"- 592mm
Rear- 16"- 546mm, 17"- 562mm, 18"- 574mm
Pic of the kit un-boxed with the added springs
So, i tackled the front sway bar first. BMW glued smaller bushings than the ones I need for my vehicle (or the brackets currently used on it.) So I had to cut them off. It was a massive pain.
Bottom being the original front sway bar, top being the new one from the kit
The kit comes with almost everything to do the front strut replacement. You need to re-use the upper hat and the swivel mount. Kit came with new upper and lower spring insulators, dust shields and bump stops.
Pic of the new front spring (left), stock spring (right)
This kit for my vehicle did not come with a rear sway bar. I did not take a picture of the rear springs side-by-side. The springs were the same thickness, same height and had the same number of coils. The rear shocks came with the dust shields, bump stops and body grommets/ bushing. It did not come with the upper nor the lower mount.
Install was pretty straight forward as I have access to all the special tools. Think my labor clocked in just below four hours for everything, most of it being getting the front struts out of the car and taking them apart and re-building the new ones. Pictures do not do the color of the springs justice. They are almost a baby puke yellow with a hint of green. They aren't pretty standalone.
I measured the ride height before and after install, both times with a full tank of gas. My car has 80k miles and I assume the suspension is completely stock. The front went from 579mm with the sport suspension to 572mm after a couple days of driving and letting everything settle. The rear went from 577mm with the sport supension to 570mm.
I took it out on the back roads and had a lot of fun. Overall, the suspension is not too much stiffer over bumps which I prefer. This is my DD and I don't plan on doing any tracks days or anything. The decrease in the lift, dive and body roll is what I found to be most noticeable.
During my back roads driving yesterday, I waited at the bottom of a hill for slower cars to get far enough ahead that they wouldn't slow me down. A guy in one of those Scion/ Toyota GT 86 things decided to do the same. He rolled out in front of me and it was on. Turn for turn, that car was slowing me down. I suspect I could have made every tight turn of the climb back up about 5 MPH faster than that car could with a much lower center of gravity.
Overall, right now I am very happy with the setup. Although I wasn't excited to drop the rear subframe to replace the rear sway bar, I wish the kit came with one. The stock one is so thin. I suspect upgrading it will do wonders. For me though, this kit is otherwise perfect. I don't want to mess with coilovers again. I just want something I can install and not have to toy with but do a great job of keeping the car at a reasonable ride height and not destroy my spine every time I hit bump.
Pic immediately after install
I can continue to update this post if you all have more questions. Hope this helps!