The larger displacement kits aren't that hard to make. MB already has pistons for 3.75 L all you need to do is make them forged for boost. The basic R&D is over.

These heads are pretty much maxed out. Check with Jerry at LET, there just isn't much to be had there. We've got a couple of sets lying around and the most we'll do with those are possible lighter valvetrain components.

Cams would be the most useful mod at this point, but without a significant interest cost is going to be prohibitive.

If you really want this to move along, pick one product and only one and go from there. There are many people on here that don't do tuning for a living that have a vast knowledge of mechanics, physics, and engineering concepts. If everyone pooled some money together and all put in a little effort the aftermarket for these cars could be huge.

This is a good thread as it allows people to express interest, but focus on one thing and go with it. If you're too spread out everything will go nowhere.