im normally a lurker on here and am in the VW community so thought id add my 2p (selling up for some OSF) and as said stretching tyres is pretty much on every watercooled VW at theminute and ive had stetched tyres on quite a few sets of wheels, biggest strectch being a 215/35 on a 9j rim.
it tends to be more a form over function thing to be honest, wide wheels are popular so an equally wide tyre wouldnt work in an arch etc. this was the start of the stretching, then it caught on as more of a look. i was never going to get the 275/40 tyres on my car that the wheels originally had and they would look like balloons so a smaller tyre has to be used in order to get the wheels i wanted on my car!
its something thats been disputed to the nth degree for years, ive never seen a tyre come off, ive never had a tyre come off, yes they handle 'different' and takes some getting used to but in my opinion are not unsafe at all (if you keep it in sensible limits, ive seen 185 width on 10j rims where inner tubes have to be used etc which i think is dangerous).
175 on a 7j is a perfectly safe stretch and probably within manufacturers limits, ive seen 165 on a 8j with no difficulties.
all drifters stretch tyres and have no issues, something to think about, used to stretch tyres on race cars too.
just a VW persons thoughts on the matter its been a while since i posted on here, my sig is about 4 years old