Thanks for the info guys, I planned on doing more research into how everything should sit before i finalized mounts, but this was more eye opening than I expected. The one downfall with the BMW trans are they dont use a slip yoke, rather a guibo bushing.
This leaves me unsure what to do. I see a lot of negative feedback from M3 guys on running a one piece driveshaft. The harmonics dont work in the real world even though on paper it should be fine. The lack of a slip yoke im assuming has something to do with it. Im running solid bushings/mounts all around, so im not sure if it would have the same effect but I dont want to drop a ton of money on a driveshaft that takes the nvh to a crazy level.
Did some digging and there seems to be a simple solution outlined here. Implementing the slip yoke on the shaft itself. Looks like this is going to be what I have to do.
https://www.proshaftllc.com/blogs/ne...on-drive-shaft
Ralliart and King, how should I go about finding the angle without a driveshaft? Or should I be able to measure from my diff to where the trans sits right now and order the driveshaft, since the minute differences in length when finalizing angle can be accounted for in the slip yoke.