This is from an apprentice panel beater. I think try to get a bomb car with rear damage. Get a drill, lots of tools, a helping hand and a mig welder. You will need to replace the bonnet, bumper, lights, well really what is damaged. You shoud be able to do it yourself. As for the main frame damage, look for the spot welds and drill them with a 3/8th drill bit. Drill only half way then a bigger drill bit half way, if ya do go full way it doesnt matter just try not to do it cause it is a pain to weld back. You will need a hammer and dolly ( block of mettle) just to do some little bashing then if ya need like raidiator and belts and fans you got a spare car so might aswell take it off that.! hopefully this has helped you!!