Welcome Klaus!! I remember seeing your stuff on dA. very nice.
Let me tell you, from a guy that does this for a living, you are pretty dang good!!!
I think your best work is the Porsche, it has so few mistakes they are really hard to find, and that is what makes a good chop... and I personally think the smoke off the tires is too much, specially considering it isnt at a track, but that is just me. I think its biggest flaw is that the rear wheel is off perspective (same problem on the Miata) but other than that, very nice, cool body design!
The Golf looks way too brushed, it needs shaprness in the reflections and more contrast... I dunno, it looks too much like a drawing, but the wheels give it off as a chop. The EVO is awesome, incredibly agressive! I remember choping that thing when it came out and I was absolutely blocked, came out looking really really bland, but yours looks like a rocket! Only mishap I see are the intercooler tubes, they are too dark, the reflections of the mirrors in the doors still depcit the old, stock one, and that the carbon fiber doesnt wave with the form of the hood, but as a design it is bad-ass.
And yes, I know I'm being an ass here, too nit-picky, but these are soo good they should all be perfect!!! Indeed, welcome to GTP, it doesnt get too photoshoppy as it used to in the good old days, but it's still cool to see people chopping stuff off in here with such quality.
Man, I need to post some stuff...