in my on going hunt for a radiator i have found this web site which we all may find usefull
http://www.carcooling.co.uk/index.php?p=home
Will a Polo rad not work for you?
It's what most people use.
If you want a bit extra cooling then a Mk2 Golf one is the same but about 2" wider. Depends if it fits in your nose cone!
Cheers,
James