Well, try as an "ordinary" AMG customer to get the wheel with the (working !) button shifting from the CL55 F1 safety car in your C 32 AMG or SLK 32 AMG. The AMG Owners Club makes it possible. Or try to have a sport suspension installed on your C 32 AMG, something which isn't offered by AMG officially. There are more examples of rebates and other advantages. I don't blame them for that, I'd do the same for my club members. But you have keep a "low level profile" to be considered a "good" member. I didn't and I got kicked. I could have fighted on that by informing AMG and my dealer but for what ? I'd never buy a AMG "sportscar", so it isn't really a problem for me.
I agree, the SL55 and the upcoming E55 are some very nice products. But if you already own a fast 996 Turbo, it isn't that much important.
Maybe I'll switch my wife's SLK for a SL55 in the future but right now I'm pretty annoyed by the little persistant problems I got with my ML55, I don't know if I'd buy AMG anymore. Time will tell.
BTW: the AMG Owner's Club is an officially "approved" Club, it is not a Club run by AMG or Mercedes.