Well after a week of not driving the cobra i decided to take it out for a ride. Ever since the header install I was convinced I had a leak somwhere, collector or on heads. I took it out and inside the car smelled fine, no smell at all. But when I opened up the hood and revved the engine I could smell exhuast fumes. Not really really strong but you could definatly tell theres a leak somwhere. How should I check where there is a leak??? I tighted the header bolts as hard as I could and I just cant seem to think there could be a leak by the heads. Is is possible that I could be smelling the fumes from the collector????? Thanks!!