I ordered mine friday, so i cant give you any first hand help yet to be honest.. i did talk to the MM guy for a while before i ordered it, and he said that the main hoop and rear bars can be welded outside the car... he said to put it all in the car (minus the door bars), and bolt the 2 rear support bars to the main hoop, right where you would weld it to the hoop and top of the spare tire well. mark it, take it out of the car, make sure your marks still line up, then weld the sucker outside of the car. He said you could just bolt it up and weld it outside without trial fitting, but he wouldnt because of flex on cars, and he said most of them have very small differences in measurements.