Quoting Jesh:
would a 1g DSM downpipe from say a '91 talon bolt right up to a VR4? or are they bent differently?
a little searching goes far.
click
As for the second post...
Some of the general components that are interchagable
Front/Rear Suspension (subframes, control arms, trailing arms, spindles, etc)
Rear Diffs
Axles
Steering Rack - Manual or Power
2 Piston front brake calipers found on 93-99 DSMs
Non Cruise Control Cables
Non ABS prop valves and lines
Transmissions - However, the trans came with two output shaft spline counts, 90' DSMs and some 91 GVR4s came with 22 spline transmissions, the rest with 23 splines. In which case you are going to need the matching transfer case with that transmission. You will want the 23 spline as it is known to be stronger than the 22 spline.
Transfer cases
There is a fair amount of parts that are interchangeable and others that are Galant Specific.