Ric

Actually, think of it more as trying to exhale through a straw, compared with exhaling through TWO straws... it's easier through the two straws. Duals basically unchoke the engine just like a bigger Y-pipe does, getting more exhaust out with less pumping effort required of the rising piston, thus freeing up more power.

As for getting a Honda... our LS1s are actually a tad better on gas than a V6 Accord.

blkZ28spt

There is more to it than that. At the power levels most of us see a single 3" Y-pipe can be plenty adequate. Where duals shine is exhaust gas scavenging. The crossover coupled with proper length primaries enable scavenging above and beyond what you can get with a Y-pipe.