Louis,
looks like the EV hat is taller than the one I have!! It may be in your best interest to get one from ebay. Its a Spectre 9849.. Cost $69 plus shipping and is a good solid piece that clears the carb.. Only thing is that it has a 4" flange.
As far as the little shot of N2O, tap a nozzle into the backside of the hat! I think a 75 shot would work just fine to help spool those turbo's!