Sorry for digging up this old post, but I just came across avisthailand.com and have the same question. For the exact same car and days, the quote on avisthailand.com is almost half of that on avis.com (US), which is tempting to me. I'm a President's Club member and how would the benefits vary according to the booking site? On avisthailand.com, it looks like there's no option to enter my Wizard number. For avis.com, it looks like benefits like guaranteed car availability don't apply to Thailand.