Sl65 - once you've experienced the torque that this engine produces you won't want a 55. I've driven a modified 600 twin-turbo with around 550bhp and that was very quick (like being strapped to a huge elastic band ) so heaven knows what the 65 is like in comparison.
Saw a new SL65 outside my work today at lunch. It would be the SL65 no question. If someone can afford it to buy one, they should be able to afford the running/maintenance that comes with it.
I've had both a CL55 (supercharged) and the CL65 V12.
The sheer power of the '65 is in a different league to the '55, much more shove. The weight is not really noticeable unless you are doing constant track days, but then the SL55 is not ideally suited to track days either.
If you are buying the car for a fast motorway cruiser that you can have some fun in then the '65 is the better car if you can stretch to it.
As for sound, the '65 has its own sound that IMO is just as good as the '55 roar.
See for yourself here what the V12 sounds like from outside:
I must just point out that I'm not looking at buying either a SL55 or 65.
It was just a point I noted while browsing Autotrader recently.
A 65 for 55 money, but obviously some people would prefer the 55. I was just curious to know what the MBClub community thought of this