Yes I have an RX-8 that I have owned since 2005. It has been a tumultuous relationship but I love her. I track her monthly on a road course and do occasional auto crossing.
And yes surprisingly enough I live in San Antonio and I can find 0w30 but 0W-40 is hard to come by but we have a ton of stores so i need to do some more leg work.
Oh, and the Mazda Synthetic is not available in the US just yet.