Welcome jonnycowboy! It's nice to see someone with your background interested in the project. Thanks for your interest.
VDrift uses a slightly modified version of the
Vamos automotive simulator for car physics. In the VDrift source archive you can find it in
include/vamos/* and
src/vamos/*.
There is some documentation on the Vamos site but it is pretty sparse. The best way to figure it out is probably to read the code, and we're happy to answer any questions you might have about it.
As for IDE, we don't use Visual Studio, on Windows we have our build setup in Dev-C++. You can read about compiling the game in Windows on the wiki here:
http://wiki.vdrift.net/index.php/Compiling#Windows
That section actually needs a little more information, you also need some libraries to compile the game correctly. I'll find the link to those soon and update the article...