Z3 Background

Loved the looks of Z3s for a long time, and love my BMW cycle, so am planning to buy the roadster as a retirement treat. Any info you all can provide on "gotchas" to look forwhen buying a used Z3? Including things to watch out for, absolute must-haves. engine size differences 1.9 vs others, etc? Primary use will be around town, plus some longer jaunts (would love to do Route 66). Sorry for being a novice, but thought tapping the forum and picking the brain of you experts might save me aggravation in the long run. Thanks for your time -- Regards -- Roadhawg