Well, you have no need for colder range plugs. You don't need 8s until you're up near 350whp. I still use NGK BPR7ESs on my car running 12.0-12.2s. You shouldn't see fuel cut at only 20psi either. Are you sure that you're only hitting 20psi when going WOT in high gears? There's more load in higher gears, so the boost usually spikes/holds much higher. To get past fuel cut, you can just get a flash. A fuel pump is good along with a flash, but you don't need it just for running 20-21psi on pump gas. It's more needed when running much higher boost - I got mine since I run 24-25psi at the track on race gas.