Originally Posted by Scottrik
The biggest difference is the 3.2R has a 2.5mm chassis and lower pod plate compared to the 2.2-ish (iir) mm thickness of the 3.1 and straight 3.2 chassis. The 3.2R chassis is a bit narrower at the rear of the main chassis plate and the easy visual reference is it is the three csk screw holes drilled around the chassis cutout between the front arms for picking up the mounting ears on the AMB transponder.
The hardware for any of these is common, so a parts car is one way to do it. There is an evolution of some hardware, particularly depending on what version of 3.1 you pick up, but nothing too bad--all the bits will fit. The key is if you have a 3.2R chassis plate you NEED a 3.2R lower pod plate and vice-versa.
Scottrik
Thanks for the info on that. I was checking out my parts car, and like you said, lower pod plate is 2.2 ish and the chassis is 2.5. I guess I'll have to pick one of those up. The car has a complete big ring diff with the red crc lowered pods, so I just assumed the lower pod plate was correct! I bought a parts car.. it was on the forum for sale with a 12L3 so I should be able to complete the car now, thanks!