A few cool modifications I noticed whilst having a browse over the bikes at the WTC in Potugal and Spain, if anyone's interested. There's probably a shed load of stuff you cant see as well.
Gas Gas
Raga's bike had a reduced cappacity flat fuel tank.
Raga's had a longer front pipe on.
All WTC bikes had the magnesium alloy crank cases.
Raga's had clear handlebar grips with the Gas Gas logo underneath, very cool!
Carbon fibre front lights.
Raga's frame looked to be a slightly different shape too, but not 100% sure on that one.
Beta
Kenny had some very nice Michelin fork protectors with like a burnt/scorched effect near the bottom.
James Dabill's had black yokes and barrel.
Sherco
Prototype Paoli forks on Cabo's bike with black sliders.
Vented seat area on rear fender.
Keihin flatslide carb.
Loris Gubian's 125 had a polished barrel an sounded more like a 290.
Montesa
Flat petrol tanks on Doug's, Fuji's and Freixa's bikes.
315 style front Showa forks.
I was told the engines are increased cc but exactly what I'm not sure.
Also told the ECU is mapped completely differently to the production bikes and Fuji's is mapped differently to the other two's.
Carbon front mudgaurd braces.
Fibre glass/carbon silencer covers.
Scorpa
More of those cool Michelin fork protectors.
Straight rear muguards.