You are going to have to go e85 if you want 350whp.
The 20g on pump gas is at roughly only 320whp and the vf52 will be the same but on e85, otherwise only 280-290 on pump, mine came out to only 287
Real ? is is it a dd, a 1/4 car or track car?
If it's a dd, I'd go with the vf52 and e85, 20g and e85 if a 1/4 car and if a track car, vf52 on pump gas or e85
Bigger turbo = more lag, no power unless you downshift, good for highway pulls
Smaller turbo, less lag, more power and no need to downshift, good for the city