GReddy EVO is another option you could go with: probably the quietest Celica exhaust available, looks great, and performance on par with the TRD Exhaust. (According to SCC, the GReddy's HP numbers were only 0.4 less than the TRD, which got the best numbers out of many different Celica exhausts they tested that month).
or try ebay. i have noticed alot of new TRD exhausts for the GT and GTS on there (standard length). i tried to win one for the GTS a few weeks back but didnt get it. so i got a Tanabe instead. and i love it!!!