Darren - good to hear you're enjoying that combo. I honestly had no idea anyone here was using it. As for the piston to wall clearance, everything I've read suggest the 85.5mm (.020).

Why go bigger?

What are the advantages?

Ghislain - I had always thought the higher CR gives you a more torquey low end, but limits your max psi from a turbo. What turbo do you use?