Not really, no. The engine was only really one point of criticism. Cost to insure, cost on fuel, "horrible to drive" are relevant to the CLK as a car, not just the engine. Although I haven't weighed them personally, I'd wager a CLK weighs more than an SLK. So if both cars have the same engine, the CLK will be worse on fuel, thanks to the weight. Handling; different chassis, weight, set up, etc, means comparing a CLK to an SLK is pretty dumb. Insurance might well be more expensive on the CLK than the SLK - I suppose it depends which is the more stolen car, which is involved in more accidents, and which has been written off more. Seeing as Rod doesn't insure a CLK, I don't think talking about the cost of SLK insurance is particularly relevant either.
So, um, yeah. Thanks for pointing that out.