Running high boost (up to 15 PSI) can waste your rod bearings rather quickly. Both of the cars needed rod bearings rather quickly. This is indicated by a knocking sound when holding the engine at about 1500 rpm with no load (neither accelerating nor decelerating) in first gear. If you must run an aftermarket pulley, it is best to limit your maximum rpm to 6000 (thus limiting boost to about 12 PSI). This will be easier on the rod bearings (ours were worn only on the top). Also, the use of 15W-50 (or 20W-50) synthetic oil when high oil temperatures are expected (as in track time where the G-60 will hit over 275 degree oil temp if you push it) will help extend engine life. Always monitor oil temperature when pushing the car extremely hard in high heat conditions.
Don't let VW's claims fool you. No car will last with oil temperatures routinely over 275 degrees. Temperature of cylinder walls and in bearings is much higher than that. Consider an aftermarket oil cooler if you take your Corrado to the track or for a driving school.
Concerning maximum rpm, we've found in side-by-side races with 5.0 Mustangs that reving the motor beyond 6500 rpm in fourth gear only delays the point at which the optimized Corrado blows the Mustang's doors off. This may seem odd, since boost increases rapidly above 6000 rpm, but there's no dyno like the highway dyno. Even with the aftermarket supercharger cam, the motor just looses too much power up there, and the supercharger is just too hard to turn that fast. Due to greater rpm drop when shifting , first and second gears may need to wind out further than 6000.