Here's a video clip of the Sportsman 400 that I race with a Hot Seat Exhaust on it.To me the Hot Seat system has a nice, deep sound to it.It isn't really loud it just has a deep tone.As far as performance goes with the pipe it did help out some, but it really works well with other supporting mods.I've never heard an Aaen pipe, but I would imagine that they work well also.Mr. Aaen makes and sells nice products and he is just as much a diehard ATV fanatic as the rest of us.

YouTube - Sportsman400


As far as clutching goes if you make a mod that moves your horsepower up or down in the RPM range then changing the shiftout will make a difference with the primary spring.It your motor makes its maximum power at 6,800 RPM and you have a primary spring with a shiftout of 8,100 or 5,800 RPM then you probably are going to be slower.It's really that simple.