E30 Touring originally came with the m40 1.6 engine with Getrag 240 transmission, I paid 200 bucks for the beast.  The first owner of the car, had M badges, trim, front bumper and a limited slip 4.45 differential installed.  Just after couple weeks of owning the car I was picked up an M50TUB20 engine, and 16x9 wheels.  With the M50 engine, I installed a M20 single mass flywheel with 5mm of material removed off, weighting around 16lbs compared to the 27 or so pound dual mass flywheel.  For cooling, I'm using an E36 radiator with an E36 electric pusher fan, swapped out the temp sensor with a single pin one for the temp gauge to work properly. I installed E21 transmission mounts with cups welded for a more stiff attachment for the transmission.  For the exhaust, I used stock manifolds off an E36, and the stock exhaust pipe mostly, using added pipe and a glass pack for now exiting at the stock location.