Hmm well, it's been a while since my last post, i've been asking a lot of questions at the ISI forums, i've been experimenting and trying things out. I got some tips about the tyres (thanks Andreas E) and now have a drivable vehicle, there is still a ton of things to do, mainly the cockpit view, dials, needles, warning lamps, mirrors etc. All the suspension is now linked up and actuating correctly. Tyres are now squishy but need adjusting/tuning as does the physics in general, although I would be happy to do the physics and indeed will certainly get it as good as I can, i'm thinking I could get somebody from the rFactor community to do a more thorough  job. Eventually I am planning to have some of the parts removeable, when I get into the damage system, (shame to let all that underbody detail go to waste)
 Currently this vehicle has 40 different parts (.gmt)and 66 textures (.dds) a lot of these textures are bump (normal maps), specular and damage versions mostly output from the main diffuse textures I have made in photoshop. Here is a breakdown of how i've shared out the texture space. All textures are power of two (square)
I have used one 2048 texture for the main body template, one 2048 for the chassis, one 512 for less important inside surfaces, one 512 for wheel, one 512 for tyrewall, one 512 for tyre tread, one 512 for dashboard/steeringwheel, one 128 for brakedisk and one 512 for windows and glass.
There will be a few more textures and some more modeling to go yet.

Heres a work In progress clip.