Well loads of info on here David. The best place to start is driving the cars, many have been in the predicament of S2k and Zed. For all the guys here the Zed won!
For 20k you are laughing, you will get pic of the specs for that. There aren't really many issues, skipping bose head unit, clicking rear axle, corroding Rays alloys to name 3. All issues are documented pretty well on here. Roadsters sometimes have leaky hoods too.
I guess go and drive the cars and then when you decide the Zed is the beast you want it'll be time to start car hunting!