At this point, all we have in stock are 70.4, six bolt RSR cranks.
The are basically a 2.4/2.7 crank that are redesigned to increase torsional rigidity so the crank can function consistently over 8000rpm.
The major design enhancement is a rod journal with a large fillet and a GT3 journal. A titanium Pankl will bolt right on. It will also accept any 3.0 SC rod. Carrillo, Pauter or even factory 911SC (yuck).

We are getting ready to place an order for more 9 bolt cranks but steel is getting hard to find and crazy expensive.