I just purchased a 91 T/A with 5.0 TPI. The former owner customized (butchered) the exhaust into some ungodly mess. I can't afford the headers now, but would like to install a new Y-pipe and hi-flow cat. The cat-back looks fairly new, but stock.

I'm open for ideas on the Y-pipe and hi-flow cat, as well as improvements to the air intake side as well. Money is an object, but not if it sacrifices performance.

99 Mustang GT (I know, I know)
93 Volvo 960 (Please, no jokes)
91 T/A WS6

The best cat you can buy right now is CarSound. On my car it outperformed the Random Technology cat by 5 RWHP and they cost less than half as much as the RT cats. I got mine for $70. The RT was around $200.