I think your car is a b6 model not a b5 as it is a 130bhp so you may get a better response there, you say you have had a new maf but why?? was this diagnosed if the cars air intake is stock unlikely to be water damaged !!! as for black smoke that suggests burning oil (blown turbo maybe????) hence poor accelerator but if the cause was water it may be electrical as the black smoke could be over fueling (maybe the smell???)but i always thought a failing air flow meter made under fueling so the best i can say is get it on a vagcom and see what error codes you get????? hope this helps a bit