Anyone used 175 50 13s before? What are they like to live with? Will they compress my spine when used with my lowered truck!!? Ive found some vintage vw alloys I'm thinking of buying, dunno whether to proceed? Will they just look daft? I'm so used to having 15s, which fill the arches nicely.

I used to run this size tyres on the Mini in Yokohama A539's, was really impressed with the tyres gave really good grip both in wet and dry and last for a while (front's usually lastest just short of a year, rears were 3 year's old still with 4mm+ when I sold it)

Drive quality was decent considering it was a lowered Mini so wasn't exactly known for it's smooth ride.

wouldnt the speedo be massivly out with these tyres?

It would affect it, but it would read faster than you were actually going. I have a set of wheels with 65 profile 15 inch tyres these are about 5-7 mph out the wrong way, I have to be careful with these on!