Hey folks, got a problem that I'm sure someone on here can help me as there's a lot of very knowledgeable folks on here who have helped me out in the past

Mrs has got a 55 plate Touran Tdi 105 model. Bought it 4 months ago and has been perfect and done 6k miles in that time and hasn't missed a beat. Had a family crisis in Aberdeen today so popped the kids to school first thing and headed up, 55 miles from door to door. About 10 miles up the dual carriageway there was a strange whistling noise about 70 which I had noticed a few times before,sounded like wind noise coming in a rear seal but it started annoying me so stopped and checked all the doors etc and off we went again. Came and went a couple of times on the way up then stopped anyway ran about in Aberdeen doing a few things and then headed home about 2 hours ago to pick up the kids from freinds. Sat at 75 all the way home on the dual carriageway and then pulled off into Forfar .50 yards up the road it spluttered and lost power. Still running just not revving right but no management light or rattles. Sounds fine until you try to rev it but sounds squealy and a bit of smoke when revved. Opened the bonnet but it's pitch black but with my phone could see the pipe on the left of the engine cover had collapsed. Switched it off as was just round the corner from home and it had went back to normal. Fired back up and still the same.

Any ideas folks?? Anyone experienced the same or just know what it is?
Got a few ideas what it could be but really not sure where to start with it and what to check. Quite happy to pull it apart if needs be but would like some advice where to start.

I would ask on a vw forum as I did sign up to 1 when we got it but I asked a few questions about more power etc and not much help at all. Forum felt a bit cleeky

Had a really shit few days and this is all we need

All help will be really appreciated