heya bimmerheads i'm buying a second-hand m20 b23 complete, just wanted 2 know what 2 look out 4 and also a of q's: >> are flywheels balanced on each engine or may i install the original flywheel on the "new" engine? >> what r ur thoughts on a couple of thermo-fans & electric coolant pump? >> can i adapt an oil coolant system from later 325i?? >> i'm suspecting corrosion in the braking system - could b lines and/or the brakes - cannot seem 2 bleed...