Michelin XAS and Vredestein sprint classic are far from a performance tire on a hot rod VW.
Yes been around forever and unfortunately they seem to last forever too.
The 145s on the front never seem to show much wear.
I'd be interested in the Tread wear Performance vs. Grip/Handling Traction Performance of the above tires.
The speed rating is important but if its rated at 125mph and the tread-wear is in the 400s you know that tire is as hard as a brick, no grip...
Imho if after 7 years on your car the tire tread is not worn out then you could consider a softer tire.
Tires older than 7 years should be replaced, rubber rots, I would not trust a spare tire with full tread that was older than 7 years.
It would be nice to find some R rated radials with tread-wear rating in the 100 to 200 range.
The bug with the 100 tread-wear rated tires would out grip the bug with the hard as rocks Michelin XAS and Vredestein sprint classic.
Since the VW is so light it is easy on tires and can accommodate softer tread tires.
I've gone through a few sets of Avon Bias Ply slicks on my other air cooled car, lots of grip.
https://youtu.be/aB9ubMvxLl8?t=3m42s