Well the reason I say it's hard is because if you've never changed one on a lumina, you don't know what needs to come off.
It would be easy if it was just the 2 bolts on the bottom, but then they throw in the bolt in the back that's got the power steering lines attached to it as well as that stupid bar that connects to the top of the engine.
Of course the only other alternator I've replaced was on a 96 blazer and I must say that was easier than anything else I have tried.
I'm new to all this stuff so when I started the damn lumina up and it worked I was proud.