also have a look at the clutch cable routing, mine was handling similarly to what yours does, i found the clutch cable routing was wrong and was touching the forks as you operated the clutch (even just covering the clutch while filtering made the bike want to steer straight on) quick reroute and its fine now

I have an 08 reg XTX with Avon Storm STs front and rear runnig 30psi in both. Get a set of Kevs fork spacers they help handling as well.
Cheers Bear.