Russ Henry
Husqvarna
AA Class
Pro Circuit is supposed to have a production system for the 310R's this week or next ready to ship and FAR racing seems to like the performance out of them over the stocker. I'm a bit of a Akra fan myself but would typically prefer an FMF over the PC, however PC is actually going through the trouble of making a system for the 310R's where as it's not on anyone elses radar yet it would appear.
I don't have much time on a '13 TXC310 but safe to say it lugs much better then the '12 and for the east coast riding I couldn't see changing the stock gearing unless for a specific hare scramble that might be higher average speed then others. I did well with stock gearing on my '12 last year so I plan to stick with either 13/50 or 13/49 depending on the wheel set I'm using (I have an 18" and 19" rear wheel/tire depending on if it's a soft race or intermediate terrain)
At the NW Husky gathering I rode Bills 12 TXC 310 with the PC full exhaust and Dave's (evergreen) 12 TE 310 that had the TXC 12 hole injector, ECU and the Akro exhaust. Dave's bike had significantly more pull low to mid and Dave had a 13/47 sprocket combo and I think Bill's had the 13/50. Dave's bike also pulled just as strong or stronger from bottom to top as the 13 TXC. I was very impressed with the Akro and it was also so much quieter than the other bikes.