2008 Mercedes-Benz SLK 55 AMG Images Surface

...Point being?

wow finally someone on this site that understands business decisions.

Well said. And in fact, the (and typically underrated) 5.4L V8 which produces 360HP is probably powerful enough for a car like this anyway. The Germans might be obsessed with their horsepower (or PS, or KW...) war, but they're also sensible enough to know that there's a time and place for everything. The most amount of power that they can put into this car without ruining things for themselves from a marketing standpoint and cannibalizing their own sales would be to take the improved 5.4L V8 from the new SL550 and put it into this car without detuning it (that engine is good for about 390 to 400BHP).... Even the 6.3L AMG V8 is probably too much in this case - I don't know if there's a 2008 or 2009 SLK63 still in the works, but anything over 450BHP for a car this small doesn't make a whole lotta sense. Of course, I wouldn't be surprised to see the detuned 6.2 V8 from the C63 find its way into the SLK if rumours of the 700+BHP SL/CL are true....

Oh and sorry, that should say 6.2L, not 6.3....

Well then they should make a new car that is in the same class as a porsche and i think your theory is flawed every car maker has some cars faster and some slower. Not all models have to be equally fast. Because then what is the point if they are all equally fast? Why buy this over the SL or a CL, or even an S63? if they are all equally fast all that differs is the size and price. And they already have a 700hp engine the 6.2 Bi-Turbo. They also have the 7.3L V12 in the zonda that is up to 750hp naturally aspirated. This car is a let down the new Z4M once fitted with the V8 will eat this thing alive.

Not necessarily, Radmeister - most German car makers try to make equally fast top of the line performance versions throughout their line-up, and while some end up being faster than others, their 0-62 performance and top speeds (and I don't mean the limited ~155MPH) are almost always more or less equal. I think the reason for this is that Mercedes, BMW, Audi, VW and the likes want one customer who needs a wagon, for example, to be able to get the kind of performance that another person buying a convertible would get. The Germans aren't exactly big on compromises, at least (and especially) not when it comes to performance. They just seem to like making cars that serve different purposes and can all go like stink. Of course you're absolutely right in that they're not all exactly equal in performance. It wouldn't make much sense, for example, to apply that same marketing strategy when they have a 700+HP SL, for example, because the next step up for the R-Class to be able to match the performance of that car would be to adopt a Twin-Turbo V12, which would cause all kinds of issues. I also agree about the next Z4M - if/when they put the E92's M3's V8 under the hood of that car it'll probably waste even an SLK-63....

there's a 30k usd price difference

The SLK that is out now, is normally aspirated V8 no kopressor, it is not supercharged .