Good morning!

I've torn apart the rear suspension and dropped the rear subframe to deal with rusted alignment adjusters, surface rust on the subframe and arms, and the rear springs (top coil on both sides rusted completely off). While doing this, I wanted to look into upgrade options that don't lower the car or make the suspension a lot firmer, as I use this car for a combination of daily driving in MI, rally cross, and HPDEs (so ground clearance is necessary sometimes). The car is a base model 2009, no traction or stability control, with just about 100k miles that has lived in Michigan much of her life.

The path I was looking at was replacement OEM springs with something like Bilstein B6 dampers, of course new OEM spring perches and bump stops, and maybe a stiffer rear sway bar (and of course the suspension links that I had to cut in order to remove them), but I'm open to suggestions that keep the original ride height and don't make things a lot stiffer.

First question though: which are the OEM rear springs? On the Jim Ellis dealer site, there are 3 part numbers: F19528011A, F19128011C and F19728011A. I think the one ending in C is correct since it's the only one that lists "w/o traction control", but the last one is only $20 vs $110.

Second: I think the dampers are original at 100k, they don't seem to be leaking but are probably tired at the very least. I've had good experiences with Bilstein B6's on other cars so they were my first thought for a durable, near original but a little stiffer option ($660 for a set of looks like), but they look like they are for an S1, (Bilstein part numbers 24-110044 and 24-110045), in which case I'll need S1 springs, mounts, bump stops, and what else? Does anyone have good experience with others? I had kind of ruled out coil overs because of the ride height, stiffness and cost, but haven't looked exhaustively.

Third: stabilizer bars. I was thinking of an R3 bar or other stiffer aftermarket rear bar, mostly to help the car to rotate on the track, but still on the fence here with ice racing and rally cross in mind

Thank you in advance!

 

To follow up here, at least in my case the part number F19128011C for the springs was the correct one, blue paint mark matching the original ones. I didn't take the risk on the $20 ones, wasn't sure I'd be able to tell any difference without buying one of the more expensive ones anyway, nor did I really want to try to set up a way of testing them accurately enough.

Oddly, the shocks all seemed to be in very good shape at least by feel (putting my weight on it vs the new Bilstein B6's anyway). There was some rust on the bodies, but no signs of leakage etc; I just assumed they were shot based on the thread about the lifespan of the R3 shocks and rusty condition of everything else around them. The rear bump stops look and feel new, with no cracking or anything else, while the front ones were cracked badly. Either way, I had ordered new OEM bump stops, mounts etc all around, so between lots of sand blasting for the rear subframe and some links, wire brushing other bits, painting etc I think at least the rear-end is ready to put back together.