I believe the stock angle in these cars for the engine/transmission pointing down with the subframe installed and the car level is 4 degrees, but don't quote me on that. Some searching on the net could verify. I don't know if the subframe is perfectly level with car itself, but I think it is or is very close. Maybe that 4 degrees is a point of reference you can work from. You mentioned you plan to point your rear pinion down, so I'd play with some different numbers to ensure you can make that work before setting engine/trans angle in your subframe. My setup worked best with my rear pinion pointed up 2 degrees and the engine/trans pointed down 2 degrees. Had to raise the trans mount quite a bit(and 'massage' the tunnel) to get that engine/trans angle. Plenty of folks using rear pinions down also. Best of luck.
