Oh dear, where to begin.
First off, I highly suggest removing caps in the car folder name. It can cause some things to completely break, although I don't remember what. Use lowercase to make sure everything is fine.
I don't know why the UI values are so misleading. The UI claims 530bhp, yet the thing makes more like 700+. CM has a function to just input in torque and power from your torque curve file, that's a decent one to use and is just a 1-click function. Also, CM can one-click generate previews for skins as well.
The tires are...fantasy. Good old insanely high dropoff with low speed, and the likes. Not sure what advice to give, apart from consulting with other physics modders and using load sensitivity curves, especially seeing as you're making an aero car.
The syntax for load curves is, in tyres.ini:
DY_CURVE=tire_SM_DY_205.lut
DX_CURVE=tire_SM_DX_205.lut
Newtons on the left, CF on the right.
For example:
0 | 1.40
3000 | 1.20
The curves are smoothed, so make sure the newton spacing is a set amount. Build it higher than the load the tire will ever see, just to make sure.
Internal forces in driven axles is broken in AC, so I suggest either leveling off the heights of the car connections in the rear geometry and adjusting the wheel points to maintain curves, or switching to CSP extended physics which has a fix for it.
Here's some info:
https://trello.com/b/xq54vHsX/ac-patch
Also, I noticed you have some stuff referenced as "Cylinder". I think it's a decent idea to rename objects to something logical as you make them in the 3D software, it's a lot easier for other modders and yourself as well.
