Re: Tail pipes
The object of a high performance exhaust is to reduce the restriction of the emissions of the engine. It's why true racing engines (not street legal) have short, large pipes that are just long enough to direct the exhaust away from the block and body of the car. Of course, this would never pass inspection or noise ordnance. The next best thing to allow the exhaust to flow freely is to open up your pipes as much as possible, which includes freer flowing mufflers, larger pipes, high performance catalytic converters, and headers.
The more air you can move through an engine, the higher the horse power you can achieve. Hence, if you have a big block engine with a small exhaust, part of the horse power you gain from the displacement is lost pushing the exhaust out the back.
Prius repellant, just add gas.