I have RE070s. They're not runflats. They're only available in very limited sizes, I'm pretty certain that you can't get them in any sizes other than for the cars that they are OEM for (GDB STi, R35 GTR, NSX, some clubsport versions of the S2000). So pretty sure you can't get them in 18" for your rims.
They grip and brake amazingly well, turn in and steering feel is fabulous. Wear isn't too bad, although I don't put a lot of mileage on. Downsides are that they're noisy, harsh and quite pricey. My opinion? I bought a second set, but only because the RE-11 wasn't released in time.