Radleigh
Ive had 2 smart cars, first one was a Smart Passion and the second one was a Smart Pulse (special edition version).
Altho I did have a little 'mishap' with the glass roof on the second one, this was the only issue I could complain about. Once you get used to the set up (ie: the lag on the turbo) then they are really good fun to drive. Extremely economical - even with me (Miss Lead Foot) behind the wheel.
For tuning bits and bobs take a look at:
http://www.smarttune.co.uk/index.php
when I had mine, Samrt tune used to do all kinds of replacement bits to tune the engine, they were also the first people to develop the Smart Dump Valve lol Very helpful people to deal with.
I have actually just this minute had my confirmation through for my new car from work; Smart Roadster Speedsilver.......... it'll be here end of October so if you want a drive in it gimme a shout