Simply taking it to a superflow dyno instead of the stutska it will show 5+% more hp.Proven time and time again stutska dyno's read low compare to the superflow dyno's.Correction factor is another issue.google it.
If you didn't plan on changing your oil and cutting apart your filter you need a kick in the ass.80 bucks is on you.
As for the intake gaskets yes Nailer should square up with you in my opinion.Otherwise have a nice day you got a gift for 11,500.
P/s no way and I mean no way should that engine fall off at 6400rpm