thrllride

i've got twin borla mufflers w/ straight 2 3/4 piping from the manifold back to ypipe..i was wondering if i would see any gains from switching from these to a single apexi n1 muffler..also if i does had some more power and sounds good i will be looking to sell my borla mufflers..its an 86 gxl.let me know what you guys think
matt