The guy I know at the Mr. Muffler by my house said he can make me a Y-Pipe that would flow alot better than the one I have for about $150. Sound like a good deal? Or should I try and give him Warmongers instructions? Either way would this be worth doing performance wise? And will this make my Borla Catback sound any deeper?

1999 MTX Cougar Stainless Borla Cat Back SPEC stage 1 Clutch kit Reverse indiglo guages w/brushed aluminum bezel Polyurethane front sway bar/motor mount bushings, Dual Mode Dampener NEXT: Cold air intake