Compomotive Wheels and tires.

Hello All. I have recently purchased an ERA GT40 wearing 17 inch Compomotive wheels shod with Michelin 335/35 ZR17 at rear. [unsure of front size as car has not arrived] These are bolt on type with around 3000 miles. I am planning to replace with 15" wheels so looking to sell. Anyone know what this setup is worth? Thanks!