What you're looking at is a $1000 money pit. Your son has probably never broken down on the side of the road or had to explain repeated car trouble as a reason for missing important things. If he's got his heart set on that particular pile of junk and you want to make it work, I would say you should let him buy it with his money and also buy him a used chevy aveo or somesuch. Register the Cheavy with the insurance company, cheaper anyway. Let him save up for parts and do most of the work himself. Learn the hard way what a broken down old sports car is all about. Plus, the Aveo will remind him every time he embarrassingly drives off to buy parts for "his car" what the implications of his decisions are.
2015 STi: Still Stock
04 STi, 04 WRX: SOLD