Nissan Repair: Tranny synchros knock grind, manual tranny, synthetic gear

Question
 I just bought a 93 5spd z.  I notice when I'm in 1st I get a thumping right in the middle of the car(where the tranny seems to be) I shift and I get a little grind into 2nd.  The Grinding usually comes to a halt by 3rd gear, and the thumping ranges in 1st gear.  It seems sometimes I can shift at the perfect interval sometimes, and sometimes the thumping can get rather loud at other times in 1st!  The guy I bought it from made me aware of it and said his friend thought it was the syncros.  I was going to buy a manual tranny on craigslist from a Nissan tech for 300 and he was going to charge me 225 to swap them out and replacing the clutch at the same time(also getting the flywheel serviced)...Any advice is good...Thanks

Answer
Greg,

If the replacement transmission is good this is a great deal.  Be sure the pilot bushing/bearing gets replaced when they replace the clutch.  Also, go with a synthetic gear grease to make the replacement transmission last.  It does sound like the transmission that is in the car is shot.