That image shows the tire size as 19". So there.They look like the 19's to me. See the last two posts here:
Also looks to be the same size as the ones on the Ken Block RS that JDRF raffled off a while back:
(check out the room on the Brembo's, they would be sitting closer to the barrel on if they were 18's, I hard have any room on the two sets of 18's i have with the Brembo's)
Yeah 18's all day long for me. The Tarmac's are already on the heavy side, surely the 19's only add more heft. Plenty of RS drivers downsize to the 18's because adding the extra sidewall adds to the comfort. And as you mentioned, better prices on tiresThat image shows the tire size as 19". So there.
However, The brand and KenBlock have some working relationship that could make it a one-off/limited run? Or no longer in production?
Personally I'd run 18, and do. lower cost tires, and I wager more options. Perhaps a smidge more sidewall too. But get the widest wheel with the widest rubber you can fit... 18x9 or 18.9.5 make for some meaty shoes. I love the 20x11's on my X5.