i'm not suggesting that no.. I am saying i would be going back and asking to see the receipt for the parts they bought, there will be a markup of course but the prices all seem way off is all. To further my suspicions of them, I just had a look on my
eper (thats the fiat parts system they use in fiat dealerships), mine is several years old now and the throttle body is listed as a discontinued part so it highly unlikely they could even buy a brand new one even if they wanted to, would have to be a random new old stock one on a shelf in a random garage, possible but very very unlikely. Nothing may come of it but its alot of money and i honestly think they have not done hardly anything or spent much at all but charged you the earth. General rule for future trips the garages, before they even look at the car tell them you want to see everything that they took off to replace and for them to tell you why, yeah they might get pissy about it but there is no real reason why they wouldnt unless they are trying to hide something. And as Eklipze3k says, there is no reason why they couldnt have sourced a used throttle body, considering the value of the car a nice garage would have at least given you the option of a useed replacement but told you it would have no warranty of any kind, would have been about £15 tops. And to add to that there is only 3 sensors on the throttle body, all of which could be changed without replacing the whole lot and apart from that there is just a fuel pressure regulator (never ever heard of one of them failing), only other thing that could be wrong with it is it be dirty - nothing there screams I MUST REPLACE THIS WHOLE THROTTLE BODY.
I guess my main point is if you don't ask you don't get, there is no harm in going back to voice your concerns over the matter - I don't use garages as a general rule but I have done and I have also gone back to complain and had refunds and looked at parts they have taken off only to discover there is nothing wrong with them etc. In doing so you should also get a feel of their character, noone likes people complaining but a good upstanding company will listen and be reasonable about it - it is afterall a customer service industry as well as just fixing stuff. If they are rude or unreasonable then you know that and you don't need to use them ever again. As someone who cannot fix their own car its always good to do this stuff, as you will eventually find a super nice garage that you can trust no matter what happens you can feel safe that they will just fix it and not charge you over the odds. Lots of horror stories out there but there is also lots of really sound garages out there, usually the back street ones that people avoid in my experience lol.
End of the day, we are all fiat people, we are gonna be biased as to what car we would keep. You do what you feel you want to and what seems the most sensible option for you - but as Purf says the main enemy of the cinq is rust, particularly around the rear arches.
So in summary, no we are not suggesting that you fork out on lawyers etc etc, just that you should stand up for yourself a bit, don't fear complaining about stuff just because you are not car savvy for want of a better term. Everything I say would apply if you keep the smart and it one day breaks down, just do not hand the car to someone with essentially a blank cheque (my wife works in a call centre for a warranty company, i can tell you they are not as water tight security as you may think, anything thats general wear will not be covered and there is come big expensive items things that come under that heading - so even with a warranty you could end up in the exact same boat as with the cinq). What is done is done but bearing in mind how much you just spent why would you not go in and say you are not happy, the worst that can happen is they tell you f'off.
ofcourse il give it a home 
