I auto-x my 318iS. I actually did the last season with an open diff, Falken RT 615 Azenis, Koni SAs, Ground Controls.
Auto-x involves a perfect match with the driver and the car they sit behind. Know the car with the basic mods, good rubber and you're good to go. No need to go swapping stuff just for the sake of trying to be competitive. I don't know if you're going to run with the BMWCCA or SCCA but it's all relative to the reason you run. Trying to win? Trying to be a better driver while having fun is what I do. I have to say all e30s are fun in auto-x. I have used a stock motor eta with an open diff, a 318iS with an LSD, a 318iS with an open diff and they all provide the challenge I seek.
This season I'll be using my 318iS with the BMWCCA and my 325i in STS or DSP with SCCA as the 5 lug swap on the 318iS puts me in SM :rolleyes::eek: if I were to use the 318iS with the SCCA