The main thing is the front windshield hole, now it can only be 50mm at its largest point. That means if you have a square hole, it cannot be bigger than 50mm measured from corner to corner, diagonally. The side FRONT windows can be opened, and as much of the rear window can be removed.
There are other rules about the sizes of fueling holes in the roof, and exhaust outlet holes.
The new rule that caught me out last time is the rear bumper height...at ROAR races in FL, they measure the bumper with the car sitting on a 20mm blocks, it can be no more than 55mm.
I [I]AM [/I]the Driver !
Murnan Modified Motors
Rocket Science Fuels
Auto Racing, Mountain climbing, and Bull fighting are the only true sports, all the rest are just games.