I NEED TRANNY HELP!!!! think its my syncros

So here it is I have a 1995 gsr and my 5th gear was grinding when i"d shift in to it so i was thinking syncro. well now what? i heard there is this thing called syncro messhed (not sure how its spelled) that can help fix it maybe. So my question is does this stuff work? about how much do u think it would cost to get all new syncros? a buddy of mine said that he would sell me his tranny from his b16 with like 65,000 miles on it for $600. should i go that way or replace the syncros? also how much would a typr r tranny be approximantley?

It's GM synchro mesh fluid, and yes it does help with grinding but no way no how can fluid fix a problem.

To have your trans rebuilt is very costly especially replacing gears, synchros, & bearings. Your best off buying a known good used or rebuilt trans with a warranty.

about how much would it cost for the rebuild or a new tranny?