I've recently had major surgery on my S3, Head/Cam belt/suspension/cooling system/brakes/paint & fianally detailed. After all that I thought it would be ok, but since I've had it back I've covered roughly 2,000kms, and in that time its been idleing erratically, the revs have been dropping to nearly cutting out when dipping the cluch when coming to a stop, and when I start when warm it cuts out after starting if I dont use a bit of accelerator till it settles, its down on power and has a lumpy delivery when accelerating. Now, progressively over the last 2,000 kms Its been starting to smell really fumey,a really toxic smell,not a oily, or rich burning smell, but now its unbearable when I park in the garage. There is no smoke but the tailpipes have a thick layer of soot on them. My freind was behind me the other day and said when I was changing gear it would let a little puff of black smoke. Today I got all the ICE fitted, Screens, Subs Amps, and Speakers (another nightmare story but I'll save that for later) and It was in there garage, they left it Idleing for about 30 mins to a hour and said the garage stunk toxic and where it was parked while idleing behind the tailpipes on the floor was about a 2 foot line of black soot??? Anyone have any Ideas on what this could be?, Im really, really fed up with this car now, I've only had it 5 months and in that time have only done 3,000kms and its been garaged 3 months of the time I've had it, Im over 10k pounds now and its soo not worth that. Sorry for the long post, just really fed up, the more and the more things go on the car , I just think that the next thing I replace will be the last and I can just have a few months of happy motoring, where do you stop and say enoughs enough !