Not sure how to sugarcoat this one, the car needs a clean start physics-wise. The dimensions are not correct, masses are not in the ballpark, centre of gravity position is out of range, car.ini is a outdated and quite messy (31kb of qlog data from loading the car up only once)... it doesn't help if the steer.lock is set to 180° by default (I corrected it for my second test run), you can't judge the handling at all with that setting. I could say that the car rolls over quite easily, rides harshly and has little body control... but I think the problem is not the actual setup alone, it's the fact that car.ini is in a state where you're not in control over what happens.
My suggestion would be to head over racer.nl, have a look around the documentation for car.ini to see what kind of data you want to search for, how to use it. Then go on a research session or two and collect as much data as you can. Check out a clean, modern day release like the updated Murcielago in the v0.835 default package, for example, and see how car.ini should look like in basic terms (what has to be there, where, what's obsolete, what are the sign conventions). That's when you can start a nice setup process for real.
Hopefully this wasn't more feedback than you were looking for, but I think it's better than telling you to keep going like that. You can always post questions here on the forums, it's not like this kind of feedback means you should give up, quite the opposite