One deficiency is inability to add or replace the single CD with a CD changer although it is listed as an available option for about $400. Regrettably I did not learn of this until I had driven about 300 miles. To change from SLK 280 to SLK 350, which had one, dealer wanted $10,000, instead of the $4,000 difference of MLP of $4,000, for models, since my SLK 280 was a used car. Beware and be careful.
Placement of instruments and controls. Ability to set seat and controls for 3 different drivers.
Ability of 0-60 should be improved to less than 6.1 seconds.