Steeing wheel buttons - great question. On the right is cruise control (standard on GT spec cars) and on the left they are for stereo control and phonekit. I didn't think any roadster came with a phone kit.... Perhaps I'm wrong. Anyone confirm?
I think the later stereos can play mp3 files. My 04 can't but I'm sure later cars could. I'd be tempted to keep the current Pioneer and put it in place of the Bose.....