WHOAH WHOAH WHOAH WHOAH!
Before you run off down into discussing Passat 16V and G60 boxes remember that you're going from rod-change to cable-change which means a completely different shift assembly, to the stick in the car, different front engine mount bracket, starter, flywheel, clutch, clutch actuation method, and the long driveshaft is shorter etc etc etc
Now, do you want all that, or do you just want slightly different gear ratios in your car?