A few weeks ago, my Benz dealer received a used SL 55 to their lot.
It didn't look stock, and having been there yesterday, I realised it had a performance package (SL 65 look) with engine power at 550hp. So I ended up asking the dealer if I could give it go
They agreed and told me to come back the next day at 11:30 for a test drive.
So after checking sum stuff over (I already drove a 350 and a 500 before, so it wasn't all new), I took her out for an hour long spin.
Well, the car is SCARY fast, and whilst I was running on summer tires in what is still very much a winter month, I was still able to do some impressive launches.
The first thing that hit me after driving off was how heavy the car felt. Whilst the engines in both cars are the same size (just under 5.5 liters), the SL has a supercharger which adds almost several hundred extra ponies under the hood. At low RPM, due to the weight advantage, I find that my SLK has a lot more ease in moving forward, but push down on the pedal a bit more on the SL, and you will hear the faint supercharger whine getting louder, and louder, and louder with a nice BRAAAAAAAP noise coming from the exhaust and engine compartment, but I find my SLK has a more pleasing noise at lower RPM's, the exhaust really has been made interesting in the SLK. The supercarger whine is a nice plus tho'
Therefore, starting from around 2200 rpm, it starts to gather pace, and when you hammer it down, the rpm's rise at an alarming rate

It's at that moment, when you go past 2000-3000rpm that the SL feels faster then my SLK, and at +4000rpm, it's just fabulous.
However, the weight has another disadvantage, namely when braking. In my car, usually pressing down on the brake pedal about a third way down will definitely slow down the car quite a lot. In the SL, doing so would only result in gentle deceleration. You really need to press down harder to brake efficiently. Having said that, I did not try any "emergency" brake procedures to find out if overall the brakes are more efficient then on my SLK (according to some reviews the SLK 55 brakes are better then those on the SL 55, and I kinda have the same feeling...).
One thing I was very surprised with, was the agility. Yes, the SL is very heavy, but it didn't feel like it when taking corners and roundabouts, only when lightly accelerating (if I compare it to my car. It's still very fast). Even at high speeds, and all of this during a relatively cold day, there was no tire squeal, no slippage... it really had a lot of grip (comparable to my SLK, so that's quite positive). I think the performance package might have something to do with this.
Finally, acceleration from stop was different then in the SLK. I think the extra weight really helps it to have more rear-wheel grip, because even though I hammered the acceleration pedal, there was neary a tire squeal or spin in sight. In my lighter SLK, depending on the conditions, I sometimes end up with wheel spin (the rear wheels really need to be a lot wider then they are for extra grip).
For those who are interested, during my hour long trip the on board computer recorder 18.6 liters to the hundred km (averaging about 50kph), whilst my SLK tells me about 14 liters...
I think, if I were to compare this to, say a Ferrari 550 Maranello, the Ferrari would feel faster off a gentle line, partly due to it being a manual (meaning the moment you let go of the clutch, the car immediately lurches forward, and every tap of the accelerator will cause it to lurch onwards). The Mercedes automatic gearbox is different in that the moment you let go of the brake pedal, the car will slowly pull forward, and only when you apply gas will the car jump ahead, always taking a little time for the autobox to take pace... you either like it, or you don't
Overall, I was impressed. Would I take this car over my SLK? well, why not. But I find there are some things I prefer in the sLK nevertheless. Would I take it over a Maranello? Once again, a hard question... The Ferrari is an awesome car and drives very differently (a bit more harsh in my opinion).
I personally consider the SL to be a beautiful Grand Tourer. Impressive performance, safe, looks cool both in and out, lots of gadgets, I love the roof technology that folds away, etc... etc...
But I do have a thing for slightly smaller and nippier cars such as my SLK
If price was not a question, I'd take the SL 55. But the price tag on a brand new SL is roughly twice as high as that of the SLK, yet the SL is not twice the car...
It's a shame really.
(pictures and video clip tonight when I upload them).