Re: Considering an '04 what should I look for?
The killer part of the oil change is 8.5 qts of Mobil1 0W-40. If you buy it yourself, you can usually find a garage or oil change place that will do the work for a reasonable price.
These are pretty solid cars if properly cared for. I looked at quite a few manual roadsters before buying the 2007 for my son. One 2005 had a clunk whenever I put it into reverse that scared me off. Another 2004 had low mileages but more valve tapping noise than I cared for. The 2007 was low mileage, under warranty, and an acceptable color that was worth the few $000 more than an older, higher mileage car.
Check every control, and esp the heated seats. Have then run it up on a lift and check for any damage underneath -- like bent suspension. Have them prove they changed the oil with synthetic -- both my used cars were non-Chrysler dealerships and both had used regular 0W-30. I made them replace with synthetic as a condition of sale.
Expect the shift from 1st to 2nd to be glitchy. Both of mine stick a little, but after 33k miles on the 2005 I can find 2nd the first time most of the time. All other gears should be smooth. At a stop, it helps to slide into 2nd and then into first.
Take it out on a flat, straight road and accelerate briskly, then take your hands off the wheel and brake. It should slow down in a straight line. Ditto for highway driving -- it should not pull and with hands off go in a straight line for quite a while.
Tires -- I'll face that next year. I drive them summer only so deep tread not so much an issue. I have 33k on the roadster and still have decent, but not snow tread, remaining.
Good luck and tell us what you do.