16 inch replica QV wheels from superformance in UK and z rated rubber can be had for less than four new TRX tires from Coker. If money no object, snag real QV wheels for another 1500 or so more. Keep your original wheels/tires on the shelf.
If you want to stay with TRX go to Longstone in the UK. They are in stock and run about $400.00 each. Much less than Coker advertises and Longstone has them. I bought 4 a few months ago. I like the idea of keeping the OEM size and type. The car handles beatifully and looks great.
Good tip! Free shipping to the US as well. Still pricey though when you consider that a set of Pirelli P Zero Rosso tires for a F430 cost only $1540 (Tire Rack). However, if you switch to 16" wheels/tires, as suggested, the price will be considerably less.