Steel wheels and winter tyres

I've been offered some 17" steel wheels with winter tyres off a 2009 A4. Question is will they physically fit on my S3, will they alter the speedo reading and will they look naff. I want winter tyres as i found the S3 to be quite rubbish at stopping in the snow last year

Thanks for the answers. I looked at them today and they're actually 16" not 17" so they're definately no good. IanMcA3 if your interested i can put you in touch, they are Nokian 205/55/16 M+S tyres. Quattro is good for setting off but i found stopping to be the hard part hence the search for winter tyres. I've found some Toyos for £128 each, Falkens for £115 each or Semperit for £154 each all in 225/40/18 92v, i used Semperit M+S when i was in Germany so i know they're good