This is SMS red sprayed over black with the intention of creating a dark suade look. The black is my own mix of Tamiya LP semi gloss black and flat black (10:3) mixed with Mr Levelling Thinners.
My wheels have arrived! These are 18" Advan RG4 wheels by Hobby Design. A little bit of putty work was needed, but overall they are decent. Male adapters to make them available with the Tamiya kit.