VW 17" wheels will fit over the brake disk/caliper on most Touaregs, but not the R50 - the gap between rim and caliper might get stones trapped and score the inside of the rim - aftermarket 17" rims would need a trial fit - I use VW Tangis 17" rims for my winter tyres which are fine - I've seen posted that there's a better choice of tyres in 18" than 17".
