Body improvement

[Ivan141]

Get a Roll cage...that should take care of the center section of your car. You could run the front bars of the rollcage through the firewall and connect them to the front strut towers, and then connect the strut towers together with a strut brace (triangular if you want it extra sturdy). You dont need to reinforce anything in front of the front strut towers.
Same story for the rear, make sure your rollcage bars go all the way to the rear shock mounting places, and weld it together, eventually adding a bar between the shock absorber mountings.
This should make your car as strong as it is going to get within reason.