I have seen the borla and Toyota exhausts, and I am thinking that they really do not do much other then change the rear tail section.  Do they eliminate the rear "canister", and anyway what the heck is that a muffler or resonator, or cat?  I know most muffler shops can throw on a flowmaster or similar in place of that and maybe a monza tip with dual outlets, and I won't even have to get dirty.  Probably only run about $150.00 max.  If the canister is only a resonator, then it could probably be removed entirely.  Anyone try this stuff yet?   

The Borla Dual Exhaust replaces the rear pipe and resonator and attaches dual piping that, according to Borla, gives better flow, better HP, and better MPG.  A universal setup like Flowmaster is likely to restrict air flow and that should be taken into consideration when deciding what to do. 

Ken
www.trdsparks.com

Ive got the Strup exhaust on mine now, which is an axle back with a pipe leading to the GIANT submarine resonator in the middle. Im also running a prototype Weapon R 4-2-1 header and S pipe. Im waiting for the prototype Weapon R cat back exhaust which gets rid of the huge resonator while upping the piping to 2.5" which would show significant changes in power.