Hi Dmytro,
a few things that stand out that are not going to work, the cross member in the front about where your knees are going to go has to be open (your legs wont fit the way you have it) Also the vertical frame members in the rear where your upper transverse suspension links are going to mount are way to high (first and second picture). Make sure when you do this that you don't overbuild it and make it so heavy you loose the performance you are looking for with a car like this. The car should be about 2200 pounds so design your bending and torsional loads accordingly. Great start!
Steve