Ok so the evo has about 35,000 miles on it and when I go through the gears daily driving I'm fine. It's only when I'm at WOT that I have problems. The gears grind a little as I shift at about 7000rpm and anything passed that the problem gets worse. Sometimes to the point where it won't even go into gear (anywhere near 8000rpm). I think I just need to replace the syncros but I'm not 100% sure. So I thought I'd pick at your brains for some advice, help, input, whatever! If it helps to know what mods I have then they are as follows:

GT35R
AMS Exhaust Mani.
AMS Front Mount
HKS EVC VI
880cc Injectors
Agency Fuel Rail
Walbro 255 Fuel Pump
ACT Street Disc Clutch
All bolt ons and supporting mods for big turbo. Stock motor other than cams.