Not sure if it got mentioned yet, but the biggest diff. is the fact the SRT-10 is a convertible!
Now, if that's not important to you, get the Z, as it's probably the better daily driver (room inside, climate control, options like Nav, XM can be factory-ordered, and it will go like a scalded cat.
If it were me, I'd get an 02-04 Z lo-mi used and save the $$ though.