Okay i already have a flowmaster 80 series and i took of the cat and placed a y pipe but it still dosent have a deep rumble like on the sound clip but the pip in place of the cat has a little leak because its not welded because i still have to take the car for testing.So i just wanted to know if its true that headers will make it sound deeper and i plan to buy a hi flow cat i was thinking magnaflow cats but does anybody know of and that out flow them. THANKS also i need to know if theres and headers that i can put on my 305 tbi engine that would also work on a 350 that i plan to put in the bird over the summer and the 350 isn going to be stock.