If you want to go faster the best way is to work on the carbon based interface between the bars and the seat, every bike has one that with a few advanced riding courses a track day or two can be had significant gains. After that set up your suspension as you are more likely to hold the throttle on further for longer if the bike is not trying to spit you off.
Exhausts there won't be a great deal of variation between the brands Termi makes some nice stuff and is usually well researched so does Leo Vince, Yoshi is pretty good too, stay away from taylor made or two brothers as then tend to fall apart quickly.