new/nearly new CLK cabrio - 280 or 350?

[AbbieCadabra]

i drove a 280 sport last night, but it was brand spanking new with only 20 miles on the clock, so it felt a little underpowered compared to my Lexus IS300 - i'm hoping/presuming it would be different after a few miles under it's belt. obviously, i didn't want to floor it too much with Mr Merc sitting in the back either!

neither of my local dealerships have got a 350 to drive so i'm just wondering if anyone has driven both & could give me a little feedback?

i'm not after a rocket ship, just like to have a bit of umph there when you need it