Not sure about rare - currently 183 on Autotrader. Rust is the thing to look for - wheel arches bottoms of doors. This is a problem on a lot of Mercedes as well so not just Crossfires. Rear tyres are pricey so want to be good or adjusted for, seat heaters break, fan controls play up. Other than that its just normal car stuff - so far this hasn't cost me anymore to run than my Skoda Octavia. I tried a MX5 before I bought the Roadster and whilst it drove well enough it was too noisy for my taste - same went for a RX8 as well.