Help find 3 inch flow tubes

I cant find 3 inch flow tubes any where. I am putting together kind of a custom exhaust with MAC 1 3/4 long tubes with 3 inch collector and 3 inch VRS x-pipe and i want to go with 3 or 4 inch dynomax race bullets with dumps but i cant find any one that i can get just 3 inch flow tubes from. And if any of you know how a 4 inch dumped race bullet will sound let me know i dont want to do it if the car is going to sound bad i just really want it to be loud.

my friend had a mac system on his car and the thing just wasnt loud enough. he had the prochamber and flow paths with dumps it sounded good at idle real deep but you rev the car up and it wasnt loud at all i want people to hear the car from a good distance away.