Another small-ish update.
Having reviewed some actual DTM wheels, I changed the design of the centre nut in the wheel. There are some errors in it so there is some lines even after smoothing but might leave them as I don't know how noticable they will be come the final render.
Clay model
Quick mock up with some materials on
Some work done on the main body too, it doesn't look like much but I have spent a lot of time smoothing out the rear. Next job will be finishing off all the rear wheel winglets and attaching them back to the body of the car. Then I can move on to the diffuser and the rear will then hopefully be finished.