it is very easy to rejet a bike for a pipe.....I would do first...before to rejet....put pipe on and move the needle clip down one until the responce gets better if you do not get enough fuel then you will need to go up on the main jet one size and then adjust the the needle for the best responce and air mixture needle....remember when you use a bigger main jet you need more AIR.....and by the way you do not need higher FUEL grade to make it go.... I have 125 with a FMF pipe, wisco piston and I run on regular grade and I can still keep up with the 450F.....good luck