best aftermarket pipe

ive heard that the factory 7 and the lrd exhaust are dynamite for blasters that have been thouroughly modified which im assuming yours is if you have a 240cc kit on it

although id wait on the other members advice as im a newbie when it comes to these things
 
f7 is a good pipe. ran mine for about 10-15 hours. sounds awesome and has lotsa peak hp, but it is a little weak in the mid and bottom end. not the best pipe for trail riding, but pretty good if you ride a lot of straightaways.
i'm running the shearer pipe now and it's got a lot more bottom and mid range power. i mean a LOT more!
sounds better than my old f7 too.