the belgian said:
On some thing the slk beats the z4, on other thing it's looses.
Exactly!
I owned the E85 back in 2004 for a couple of years, then the E89 for 4.5 years and wanted a change. I'm not brand loyal and like to take a subjective view on things... its all about weighing up the pros and cons.
If you're cruising along in 7th and ask for a little power, it might drop back to 6, and this happens pretty quick. If however you ask for a lot more power, it thinks about it... keeps thinking about it, thinks about it for a bit more, then wakes up, drops back to 4, the revs shoot up and it shifts you along at great speed!

You'll soon learn the shift points and know when its going to change. From stationary it always moves away in 1st, but if you slow down to about 1mph, it will move away from there in 2nd gear.
Strangely just a couple of days ago I got an email from Mercedes saying that a service was due in 30 days, which actually coincided with the car telling me, and the car even asked if I wanted to phone Mercedes Glasgow to book an appointment! (phone connected via bluetooth)

I went online to the booking process and it seems according to the details I entered, the first yearly service is £266. If I want them to collect it and drop it off, its £316 !!
No kidding, with the roof down the engine sounds great from inside the cabin, sounds growlier with the roof up!
Good luck!
