I own an early normally aspirated 16V which has 15" alloys as standard. As I need to replace the tyres I was thinking of changing to the standard 16" alloys from the 16V turbo or 20V cars. Can someone advise if I can do a straight swap? Also, is the tyre size I require 205/50/16?

yes and yes

If you hve 20V wheels 225/45/16 is the other tyre size option

Many thanks for the info.

I have a 20V with a set of 20VT 16" wheels for the summer; the original 15"s are still used with the winter tyres. The larger diameter converts the rather optimistic speedo to one that is just about spot on with a steady GPS reading on mine - so be a bit more careful The other downside is that 16" tyres are noticably more expensive here.

The 20VT wheels seem particularly light and certainly don't harm the handling. It is the only option that was not available from the factory that appealed Eventually I got a set and had them refurbished. Makes the car look better but still "sort-of" not played with.

OK. Thanks for the info. I need to check tyre prices for both 15" and 16" options before deciding how to go ahead.