I've got a Maximum ST, it's a good little truck that I got on the cheap and I'm really happy with it so far. It's got the Torq 12 engine and that engine's good enough for a while. The truck came with both the origional muffler and a duratrax tuned pipe, supposed to increase mid to top end power. Well I just got a nice new body that looks sweet to replace my old shot one, but that aftermarket pipe is huge. It curves around and goes forward, where the origional one was just a little can behind the engine. Now I don't want to cut a hole in my nice new body just to fit the aftermarket pipe, but I'm concerned about potential performance losses. Can anyone tell me from experience whether the aftermarket pipe would make a difference on power, if any, or is it just a novelty more than anything else? Any experience from any of your trucks would be great!

run the new pipe on your car and if its better power over the stock pipe and you like it then cut your new body and just keep the new pipe on

Put the tuned pipe on! I also have a Max St but its a pro that came with the tuned pipe on it. You can adjust the tuned pipe. Press the pieces together under the coupler and get more low end torque. Pull them apart 3/4" and you get better top speeds. I press mine together off-road and spread it when on road. You do have a diferent engine than mine but I think it works the same.

As far as your body is concerned. If you cut your body right the tuned pipe looks cool. All you have to do is let the little tube stickin out of the side of the exhaust breath. Also the stock max st bodies are shaped to go around the exhaust so it isnt seen.