I own a 1980 Peavey T-60, and will within the next 6 months own an Ibanez ART100W (hopefully =P). I've got a few questions on string action for both of them.

1. What's the lowest possible action for both those guitars?
2. How do I adjust that?
3. What am I sacrificing when I lower my action?

I build finger strength by practicing on an acoustic with ridiculously high action (about 6.35mm at the 12th fret) and I like being able to have that kind of conditioning. Like a runner with ankle-weights y'know?

Thanks a lot!
Learning more about music and all its glory one post at a time.
The action height is more or less dictated by how good the fret leveling job is on the guitar, so if you want low action, just take it as low as you can without buzzing. The way you do that is by lowering the bridge. However, if your truss rod isn't adjusted properly, you will be limited in how low you go without buzzing, and also if your nut slots are too high you will NEVER get as low as you would like.

The only sacrifice I can think of in lower action is something my friends call "digging in", as in on a bend. Personally I find no loss in "digging ability", but if your actions is too low, the strings will buzz and you will loose sustain. This is an obvious drawback, but you don't have to set it so low that your strings buzz. Just take 'em as low as you can without buzzing, there's not really a negative side to doing that, as you get the benefits of lower actions and now sustain killing buzz.

Good luck.