the difference between my old saph and my yellow M3 was night and day. and that saph had a fairly decent setup for a road car. i'd say youre looking at at least a proper rear beam and adjustable front setup to even think about similar levels of mechanical grip and "handling" also the sierra is a lot harer to slide than the M3 so be prepared to spin rather than powerslide.

also persoanlly i'd say youd want a fairly LAGGY setup for it to be more fun, if you try and replicate the power delivery of the M3 youll just fail and be dissapointed, if you get good old fasioned tuebo lag it will FEEL faster and actually be more fun (IMHO)