Do Lower Profile Tires affect Speedometer Reading

[mboucher70@hotmail.com]

I'm looking at a pair of 'performance winter' tires.  The size is 195 55 R15.

My car's original equipment is 205 60 R15.

I've read that for winter you should change the sizing by one each - that is either

205 60 R15 or
195 65 R15 or
185 70 R14 if load capacity allows.

I'm a bit confused by this rule.  I understand that the tire profile change is ofset by a rim size change.  So then, wouldn't 205 60 R15 and 195 65 R15 give different speedometer readings, since the rim size is the same but the profile is different?

Bottom line question is will moving from 205 60 R15 TO 195 55 R15 work on my car (1990Audi100) or will it change my speedometer readings?

Other question, where is a good place to get inexpensive winter rims (Wal-Mart, etc)?  It uses 6Jx15 rims.  Are these standard rims, or specialized Audi rims?  I've noticed that most Audis use the 5-bolt tires, but mine uses a 4-bolt.

Thanks

Charles