Have you considered having your original exhaust manifold modified for duals? It's a fairly simple job for someone with good machining/welding skills. A slot is milled in the manifold for a blocker plate to separate it into two sections, a hole is drilled in the front section, and a second pipe flange is welded over the hole. The simple way to handle the situation would be to have a muffler shop fabricate a "Y" pipe to put two pipes out the back. The dual exhaust just adds twice as many parts to wear out with little or no gain in power. The exhaust note with duals does change a little, but it's just noise, not more performance you're hearing.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!