The arms are shoved into the short wheelbase position and, at least with regular white arms, they're bound against the chassis tub. Also there's an axle clearance issue, as the GT trans is slightly higher so the mounts are not clearanced, not to mention rear bulkhead clearance issues... And should you be fortunate enough to find the discontinued RPM T2 arm mounts, they use the outermost holes which involve redrilling the chassis...
All can be worked around, but maybe not worth the hassle. The other alternative is to find 0º arm mounts and use 3º 10T hub carriers, which may be easier to source although still discontinued.
*places unopened can of worms back into cupboard*
