I put a FMF on mine. Keep in mind you are not going to much much more power out of that motor unless you bore it. Still it's a fun DS bike.
I wouldn't recommend FMF headers to anyone. They SUCK. I bought 2 sets of them and they both leaked right out of the box.
I sent them back over 2 months ago and STILL haven't gotten my money back. Stupid -heads!!!
If they were the only company left that made any aftermarket OR even OEM parts for my bike, I'd either find a way to make whatever it is myself (like I did my headers) or I'd just ride the bike as long as I could then junk it out.
HEY!!! FMF Racing!!!!