I depend's on the application. I've heard & seen video's of an auto mk1 running 9's on stock driveshaft's & C.V. joint's. This same car was a daily driver when it was running high 10's.

An auto is no where near as hard on drivetrain's as manual's.

Saying that, I've also broken to mk1 GTI close ratio gearboxes with bugger all power & I wasn't even hard on them.

Had a stock mk1 diesel 4sp & that copped an absolute hiding & it didn't miss a beat & that was with 130hp.

Also, I currently have a mk2 020 with 100mm cv's fitted & I'm yet to have broken anything in it & it's had a very trumatised & abusive life!

It does crunch in 2nd though. Standard issue, even in the current gearboxes.

020's are luck of the draw or russian roulette I reckon!

If your kind to them, you shouldn't have a problem.