dont ever think about it as it will give you issues you will not like at all
you will need to change following because there not enough slack on rocket 3r with following
brake lines, they are longer for GT version
hydraulic clutch line longer for GT version, (will require opening a lot of stuff not easy)
wirings for left and side of handlerbar, its longer on GT compare to R
From what I have read in groups, adding the GT bars and not changing to the GT seat puts you uncomfortably close to the handle bars. I switched my GT to mid controls. Best decission I ever made.