well cobb would prefer me to have a catted downpipe and stock air box.im buying the stock airbox off of the original owner tomorrow and hopefully be running on stage II tomorrow night.Stage II is supposed to bump me up 50-60 more horse which takes me from 11.5psi to about 16psi.The thing i gotta watch out for since i have a offroad pipe is boost creep.So thankfully i have that boost gauge so i can keep an eye on it and if it starts to creep to like 18psi ill back out of it.