:hmmm: Probly a matter of personal opinion. How bad is your roof? Are you any good with a hammer and dolly? lol
IMO, I'd fix the roof thats on there, after changing a rear quarter panel on my VY I found that its better to repair what you've got instead of replacing. Its just a heap of mucking around that could be spent on fixing/panel beating the roof thats on there. That way its still all sealed, (reasonably) rust proof, and you don't have to muck around lining things up.
I wouldn't just bog over the dents, definately try and panel beat them out some, then a thing skim over the whole roof.
But, thats all just my opinion, I'm not a panel beater and am not going to be spending hour after hour panel beating your roof
lol,
They can remove all the dents in the roof paintless dent removal/rub them out, so it shouldn't be too hard to fix up for a panel beater.