When to re-jet?

[888]

I'm just about to get a Yamaha TTR250, and the dealer is going to put on the Yamaha GYTR Slip On Exhaust- do I need to get the bike re-jetted at the same time? The dealer doesn't think so, but I'm not sure.....

Additionally- anyone have any idea what (if any) hp increase the Yamaha GYTR exhaust will add?

[klx kid]

everyone i know that has changed exhaust systems have not changed their jets. and i think the GYTR's add 2.7hp.....but i dont know if it is the same for TTR (the 2.7 is for YZF's or atleast some of them)