I have used interparcell.com a few times which is a bit cheaper. x4 MR2 Mk1 wheels with tyres will require 2 packages of 60x60x50cm @ 19KG (guessed weight) and usaly works out at around £8 for x2 wheels. So x4 wheels delivered in 2 packages of x2 wheels is about £16. Just tape the two wheels together, add carboard to protect the face and stick on your lable! You will need a printer.

I have had some problems with them recently not collecting at one adress, but they have been prety good apart from this recent issue.

Apparently 'Interparcell Ecomomy' is a better quicker service, but a little more expensive.

Hope this helps!

Daf