I thought the TRD system was really a Borla exhaust system anyway. I know that Borla makes a cat back system for the V6, I have one, and it's great. I read somewhere that the TRD system was made by Borla but unfortunately TRD only comes in the V8 version.
So if you want system that of the same high quality for a V6, buy from Borla, only difference is the ends don't have "TRD" stamped on them.
Someone tell me I'm wrong if I am out of line.
GL -TM-