ok, here is the deal, christmas is just around the bend and im trying to figure out what to suprise myself with, I have a z400 with a full yoshi exhaust, its jetted, and has a k&n with no airbox lid and an outerwear, i also have a new ignition with the rev bumped up,

I like my z but would not mind if it is faster, I am thinking i want the intake and exhaust cams from hotcams, but i have some questions, like, would i have to rejet, and how hard is it to put new ones in, what kind and how much gains will i get.

i could really use some help