I have an A4 S-line quattro which has been to modified to around 260bhp (various work from the superb guys at AMD). During this hot weather I have started to experience problems when acclerating in 5th and 6th gear over 5000rpm. I realise this is high speed, and I obviously don't make a habit of it, but recently I was on clear dual carriageway and thought how does this car go. Well over these revs it was awful. Turbo cutting in and out it seemed. I've been back to AMD who are changing a pipe for a metal on. Turbo intake i think but can't remember. Has anyone else had similar problems? I know a few TT's suffered a similar thing.