OK, so I have a 2004 Gt with o/r x-pipe and Flowmaster American Thunder Series. It's just not loud enough. I traded my SLP loudmouth catback for it because I wanted more of a controlled sound and it's nice but to quiet. I wanna buy some used flowmaster mufflers and get them welded in place of the old ones. Does anyone know of a good series or another type of muffler that has good volume because I don't know too much about Flowmasters. But it has to be something that is a direct fit. Thanks