My truck has 8.6cr, I plan to run high boost one day as well. Making a few changes, then I'll crank it up where it needs to be. The truck felt fine under NA driving as well, when I used to drive it on the street; of course it's not real heavy.

I think both of those engines will make good power regardless. Get tires or suspension for hooking, don't let traction determine which engine to get.
There's probably no difference between those two engines when they are being forced fed air.