I went back to the wider OEM wheels on my STR. I have a set of ASA JH3 wheels 18x8 with Michelin Pilot Sport A/S PLUS 245/40ZR18 tires that came with the car. They have 80% tread left [8/32 inch tread depth from original 10/32 inch tread depth]. You can see them on ebay:

Set of ASA JH3 w/ Michelin Pilot Sport A/S PLUS 245/40ZR18 fits Jaguar S-Type R | eBay

or just search on ASA JH3

I really liked their look but can't get them in a wider rim [sigh].

cheers,

TonyL