I got a 99 gsr with tranny that grinds in third( due to my dumbass cuz powershifting it). I was wondering if its worth it to get it rebuilt with carbon coated synchros or am I better off getting another used tranny( something like a ITR Or another GSR)?

 

Unless you are rebuilding it yourself, it will most likely be cheaper to buy another transmission. Have you changed the transmission fluid recently?