Dyno results...making changes..need opinions

Hey guys

Just got back from the dyno here in Germany (I'm stationed overseas).
On a Superflow dyno I put down 350 rwhp.

My car has a:
-Vortech SQ supercharger
-90mm maf
-bassani catted(cats are gutted) x-pipe with flowmaster 40s

So people here have been saying I should be putting down more than that.
Just today I pulled the spark plugs and noticed they were stock!
Tomorrow I'll be putting in new NGK-TR6 plugs gapped at about 32 or 33.

I'll also be getting an afm powerpipe.

Should I be close to 400 rwhp with the RIGHT spark plugs and the power pipe?

Also..it has stock gearing. Are 4.10's good on a blown 4.6(manual)?

thanks
Patrick

Forgot to mention that...everything was upgraded accordingly:
38lb inj and 255 lph fuel pump.

I'm guessing it was the mongoose kit.