I am older and have a kid but I can still sympathize with your situation. When I was 16 my dad had the option of getting me a 90 5.0 mustang with bad paint for $1000 or an 89 v6 probe with better paint for $2000. Against my wishes he got the probe. When I turned 18 I sold the POS( luckily it was in my name) and began my crx build. He felt disrespected and cut me off from any and all financial support. Offer to buy the car off your parents or get a new car. If they dont understand now they will never understand. We as car guys are different. Its either in your blood or its not. You will never convince them that its therapeutic to build and drive a nice car and they will never convince you that its pointless and just sucks your wallet dry. Best of luck