I've got 351W (E.DI.S. by EFI Guy), 4R70W and NP205. No holes in my powertrain... ;D
You will want to regear for sure. I'm running 35" tires and considering going from 4.56 to 5.14s over the winter...
Its past my bedtime so I will post more tomorrow. You will need a custom cross member but...