1) Pro-flow adapter w/foam filter.
2) Rejetted with Dynojet kit (followed their reccomendations for altitude).
3) Cut flap out of snorkel - no other airbox mods.
4) Engine - stock.

It seems to run great with no issues

 

I left the old gaskets in. Yes you have to rejet it. I have the pro flow k&n with the air box lid off. Runs great.

 

I left the old in and didnt leak a bit - how tight did you tighten the nuts?