Not sure if this will reassure / help.Have had my S1 for three years now. Bought from Williams and appeared in excellent condition (which it was).
Since then, MAF needed replacement very soon after purchase but symptoms a bit different. ECU went into limp home mode if I hit 5,000 rpm, switched ignition off, then on again and all was well. Anyway new MAF has sorted that. Then the dreaded click on trying to start, combination of corrosion on the earth terminal located behind the washer bottle and need for a new battery, apparently the battery that came with the car was for a golf buggy!!!. Since then I keep the new battery on a trickle charger and it has been good for the last three years. Last year, Heater control valve seized through lack of use in the winter (replaced) and Air Con stopped working but this was a simple re-gas job. So all in all, pretty good experience and have covered more miles in my three years of ownership than the previous 11 years of the previous owners.
Stick with it, once you have these niggles sorted you have an incredible car. My previous cars were Aston V8 Vantage, beautiful car to look at and drive but you need a cheque book with several zero's added to the end of each cheque to run it. And prior to that 911 - the ultimate example of auto engineering and drivability but of course lacking something in the soul department. (Also had a trad Plus 8 for ten years, lovely car provided you didn't push it on bumpy roads as in my opinion it then became terrifying.)
Aero's fill a gap very very few other cars can fill, at least in my opinion.
