Hello, sorry to revive an old thread, but was this successful for you?
I've called SPG customer service 3 times, and even confirmed with a supervisor -- all 3 of them have said explicitly that there is no way to attain Preferred Plus unless I have an Amex card, and that AAA doesn't change status. All it will do is give me the best rate. They did take down my membership but it doesn't reflect a status or tier change in my account, so I'm just wondering whether you managed to get this to reflect in your account? Thanks!