Eurotuner Magazine April 2011 issue had an article on tuning an E36 1992 325is for track work. Or more specifically tuning the car with the view to making it a track day car.
They started off with a baseline lap and added modifications through the day to see the difference it made to the lap times.
1st Stage: Performance brake pads from Cobalt, slotted brake discs from TMS, TMS braided brake lines and ATE Super Blue Racing DOT4 brak fluid
Difference from stock: 1.43 seconds faster
2nd Stage: Privat alloy wheels & wider tyres
Diff: 6.5seconds faster
3rd Stage: PSS9 Bilstein coil overs. Height and damping adjustable. TMS front and rear anti roll bars, E36 M3 strut mount and 2.5degree of negative camber. 1995 M3 offset bushes for increased caster. On the rear, stiffer trailing arm bushes, 1.75inch drop at the front and 1 inch drop at the rear.
Diff: 3.3seconds faster
4th Stage: UUC Corsa cat back exhaust, AFe cold air intake and TMS ECU performance chip
Diff: 5.5seconds faster
Impressive improvements but it should be noted that TMS’s own race driver was driving the car so you could not say the test was completely impartial.
StrikeEngine E36 Tuning Guide