You dont need to re-gear the syncros; Just change the FD to something a little taller. I guess in your case the 4.6x

My car has a 4.08 stock and I am currently running a 4.36 (both are VLSD) and it made a world of difference. I sit 400 rpm higher at any given speed than the stock gear. It shifted the rpms right where I want them for my car so I dont have to down shift nearly as often when going through corners. My car also only runs to about 6800revs but I usually shift at 6400.

But I can also change out F/D's in under 45 minutes and have 3 to choose from - 3.90, 4.08, and a 4.36.