It can use classes just fine, using d20 Modern definately helps with that. I agree on the hit points, using the damage save system from Mutants and Masterminds could be the key to truly converting shadowrun over, but it can use hit points just fine, but it won't have the same exact feel. Then, to hardcore SR fans, even using the damage save for health and magic drains, it still wouldn't be 'true' Shadowrun because your using d20 instead of d6's. Personally, I could care less about the die mechanic difference, as long as a translation was true to the feel of shadowrun. To me, I can get the feel of it with and without hit points, but incorporation of the damage save would work for me.
Anyone have the rules for the damage save?