You could try contacting some of the Brit/Irish/Euro distributors/vendors.
But, when I was looking for a set of Speedline 2120s for this car, they NEVER EVER got back to me/answered ANY emails, or calls, at all (so, then I just bought the Dekagrams).
SADLY, like many other items (cough, cough; Direzza D3s), Tire Rack is given the absolute EXCLUSIVE on the whole OZed/Sparco lineup sold here, and THEY get to choose which items they want to sell, and refuse to bring in anything outside of that 'roster'.