The Mercedes SLS AMG won't ever be mistaken for one of the company's fine sedans--not even for the relatively compact SL or SLK roadsters.
There's just not much room inside either the SLS AMG gullwing or the roadster, though it's long, low, light and wide. Two medium-sized adults are it, and they should travel light.
At 183 inches long, with a wheelbase of 105.5 inches and an overall width of 76.3 inches, the SLS has the approximate dimensions of a C-Class four-door. Most of the length isn't left for passengers, though--it's left to the front-midship engine, with a short cabin for the driver and one rider. The SLS also is just under 50 inches tall, which makes headroom one of the few luxuries it doesn't offer. Leg room is even more lean, and most people will sense the lack of space when they try to adjust the SLS' power seats for more knee room.
With the Roadster roof lowered, the car's dimensions are easy to get around, and to get in. With the gullwings, it's a different story. You'll need to practice getting in and finding a comfortable spot: first, lean down to find the gullwing door handles, down by the sills, lift them without clocking yourself in the head, clamber in--again, watching out for the lower door panel. Hopping out requires the same thought and effort, and even so, we've still counted more than a handful of head-door collisions. For fun, you can open the gullwings under about 30 mph, but a warning beep suggests you consider otherwise.
Just shy of claustrophobic, the SLS AMG at least has a power-adjustable steering wheel, and the seats are large and very nicely stitched in fine leather, with firm bolsters. Storage is on the light side, with just a small glove box and a shallow console bin at close reach, and some netted pouches for other less precious items. The trunk's about what you'll expect: in either body, it's just more than 6 cubic feet, and will hold one set of golf clubs, or a couple of soft-sided bags.
Fit and finish is flawless, even with complex trim like carbon-fiber panels meeting up with chrome and leather. The SLS AMG is by no means quiet, though, and if you're looking for something that can't rattle the tiles off a deep mountain tunnel ceiling, maybe you'd be more interested in a CL55, anyway.