Foreign cars are just stupidly expensive, especially the German breeds. If I had the 90 grand just laying around, I'd pick one up. Otherwise, no thanks.
BTW, the Challenger is built on the exact same frame as the Charger, albeit 4 inches shorter. It drives exactly like a Charger as well, there is very, very little difference(I've driven both SRT versions, non-modded). They are also pig-heavy, being well over 4k pounds
The only good thing going for them, imho, is the look...I'm not a big fan of their Hemi-derived engines and they are much more expensive to modify compared to their Camaro/Corvette/LSX and Mustang/4.6/5.4/5.0 brethren.
In terms of engine peformance and ease of ability to modify, the Camaro is king. Its engine was able to put up over 800 crank horsepower through a supercharger with stock engine components...reliably. I'd get the tranny beefed up though.