I currently have what my garage calls the 15" anniversary wheels on my car

(diamond cut).

Unfortunately they are oxidising quite badly and was wondering whether or not they can be refinished back to there original condiition.

If not, I am thinkng of getting a new set of wheels, possibly with bigger rims but do not what to change any of the suspension setup.

Can anyone advise me as to whether or not the handling of the car will deteriate.

I was thinking about ether 16" or 17".

Regards

Baz