SPF have 18" rims as an option.
they look terrific...
NB: they also come "not polished" if you prefer...
http://www.hillbankmotorsports.com/s...18-wheels.html
See them on a car...
http://cgi.ebay.com/ebaymotors/Super...-/270517687970
I believe Cameron formerley "Cobra 88" ran these on his SPF with great success.
Not sure if they'd fit on a CR, but looked good on an SPF.
Best wishes