a 150 mite be just fine.

Ya know, Im gonna wait & see what Lancer or someone else says on that. I wouldnt be afraid to try it, but, Id`rather have the blessings of one of the real tuning guys.

Are you just shooting in the dark, or do you have evidence you need to rejet ? Not taking away from the tuning experts here, but even they would have a hard time telling what your bike actually needs for jetting. It depends on your bike first of all, then altitude, and several other things determine what you need.
I did a spacer mod only, because thats all it needed, (to correct low speed surge) and.....just for info, that did not change the backfiring one bit.
Changing to a less restrictive filter is no reason to rejet,......unless you do a lot of WOT, because that is the only throttle range where it will make any difference....if there. Even a modified exhaust will only make a difference at higher speeds,....and is not a reason in itself to rejet.
I know, others have different opinions about this kinda stuff.

Thanks guys!