Mercedes is taking the fight to the seemingly indomitable BMW 3-series with this, the next CLK coupe.Previous generations of CLK have always majored on comfort over dynamic ability, but Merc's hoping that new car will trump its Munich rival on both counts.It's certainly off to a good start. The new CLK is based on the same underpinnings as the new C-class saloon, which means it's got the best chassis in the class.It also means it should have improved interior space over the previous CLK, which was never quite as roomy as its rivals.The engine line-up is likely to match that of the C-class. That means you can expect four- and six-cylinder turbodiesels, plus four-cylinder supercharged petrols, a 3.5-litre V6 petrol, plus a V8 CLK500 – as captured by our spy photographers.There will also be a new CLK63 AMG, using the now well-established 6.2-litre naturally aspirated AMG V8, and packing over 450bhp. Some of the components of the current CLK63 AMG Black Series have made their way into the much-lauded new C63 AMG, so expect the C-class to return the favour.If the new CLK63 AMG is as good as its saloon and estate siblings, expect Merc finally to have a real M3 rival on its hands. We can't wait to find out, but with the new coupe not expected to arrive until summer 2009, we'll have to sit tight.