installed it on my 03 cobra with 300 miles on the car.it is a off-road x-pipe no cats,also installed those mil things on the o2 sencers.the car has the stock cat back on it and it sounds really wierd,kind sounds ricey.here is my question when i got done with the install i started the car.started fine ideals great but for the first 30 minutes it smoked like a freight train then cleared up no smoke no more.do you think the car had to learn how to run again with out the cats?or was it just cooking off the coating of my bbk x-pipe?i will say this the bbk x-pipe fits like a dream and hangs tight to the floor of the car