[Gumby]

The amount of power realized by replacing the stock flexpipe will vary depending on the level of modification. If you have not fully reworked your engine it's probably only worth a couple of horsepower, depending on the dyno and roll time used. Seat-of-the-pants dyno is my perferred system, and I doubt you'd notice the difference unless you were at the track. For the cost involved you are better off saving your dimes for an engine biuld (NA, Turbo, SC) and worring about the flex later. Personally, I'd rather make my own. The ones out there use the same routing as the stock one, which seems to be more of a restricting factor than the diameter of the pipe itself. With some header wrap on the pipe and some heat deflection on the steering rack it is possible to signifantly reduce the amount of bend in the pipe, thereby drastically rducing backpressure. Using a slip jointed flexpipe instead of the shitty corrugated ones that are out there would be worth it as well.

but that's me...