hm the 265/60 ZE912 must be a new one within the past year, def was not available when i bought my tires last august. Hopefully they improved their rubber compound though. i have seen many 236/60/16s and larger come back for premature wear (about 40k when they have a 65k warranty) but never had any ride or traction complaints so you made a good choice for a tire on a vehicle for sale. if you dont mind me asking, what was your out the door price with mount and balance?
the stz04 is available in a few sizes larger than 285/60/18 (31.5) which is what im running. they are also available in
265/65/18 (31.6")
275/65/18 (32.1")
265/70/18 (32.7")
275/70/18 (33.1")