ORIGINAL: fireblade
I hadn't realised that the S wheels were smaller but they cost a considerable amount more to add them to the "ordinary" Turbo and I think that it would lower the trade in price when you come to sell.
However as you say the depreciation is horrendous anyway!!
Cheers
Sorry not to have made it clear, it is the turbo wheels which are slightly less wide than the S wheels; tyres are the same size.