Steve, it is very interesting that you started this thread.
I actually approach it from a slightly different perspective. I do not care for the look of the AMG GT. I personally just don’t care for the big shark mouth front grill, which apparently is getting increasingly popular with Mercedes and Lexus.
I am not a big fan of Mercedes models in general, but I just happen to love, love, love the characteristics of the SL. For me the SL is small on the outside but large on the inside. If you check specifications you might be surprised to learn that the SL has more legroom than the front seats of most of the Mercedes sedans!
The SL as a large two-seat convertible with a retractable hardtop literally is a unique vehicle. No one else makes a car with this exact design brief. (Okay, I think one of the newer Ferrari models may be a large two-seater with a retractable hardtop, but I cannot consider that a daily driver for reliable, high mileage use.)
As far as I know the SL is the largest two-seat convertible in the world. Many convertibles are 2+2, but I don’t care about the rear seats, and the 2+2 results in reduced legroom for the front seats.
It is not that I have such long legs, obviously, but I like space. I have never cared for the genre of smaller two seat convertibles (Audi TT, Audi R8, BMW Z4, Porsche Boxster, MB SLK, Jaguar F, etc.). I find all of them annoyingly small and cramped on the inside, whereas the two seats in the SL feel like the front half of a large sedan.
For a relatively small car on the outside it swallows a serious amount of luggage. The trunk accepts my giant 29” full-size suitcase on wheels. And you can stow two small to mid-size suitcases behind the seats.
Finally, I love the retractable hardtop. I just find there to be too much wind noise in a soft top convertible to be used as a daily driver in which I am almost constantly on the bluetooth telephone. Yes, the retractable hardtop makes the car heavier, but in cost/benefit analysis terms I love the solid weatherproof seal, the noise isolation from the outside and the physical security of a steel roof.
I bought my SL550, named Gunther, new in 2008. My personal dilemma/annoyance is that the next generation 2020 or 2021 SL is going to be a 2+2 soft-top — exactly what I don’t like and I don’t want!
And just to make it worse I really don’t think the current SL body style with its gills and sharper angles and body panels is as pretty as the smoother, simpler body style of Gunther and of your high-power SL.