Wow, Tom! That's hot.
About design wise:
To get pure DTM you should add tons of damn small wings and other aero things. Looks like you're going for it, nice ;D
There are some nasty places like this thing on side of the front bumper or this (dunno name) line going thru side of the body. I'm sure you can get it better
Hay Tom. I have been watching those pictures for quite some time.
Love the air intake for rear wheels, and all the details, bigger Citroen sing on the trunk(now it looks better), But those wings I don't know, look ugly... may be if there is less wings, may be make them little shorter?
Dunno well see what others think but I think its ugly
I must admit I wasn't really aware of the Citroën C5 Coupé. The car car looks really good. The stock one and yours. I would prefer the DTM version of course . The part behind the rear wheel is kind of interesting. The flat door is another great looking element. Cool ideas. I'm eager to see more.