How can you have parents AND a significant other dictating your life at the same time? Sounds like you are suppose to be in those in-between years where you get to be stupid and have no one to answer to but yourself.
Have you checked out the prices of new cars lately? If you scale back your mods to the car and just drive it, do you think you will average less than $500 a month on repairs (not to mention added insurance)? How much money are you really going to save buying a different car with a different set of problems?
Man, live life when you are young. Wait until you have a wife and kids to start sacrificing your own interests for other people. As a wise man once said, you ought to be out riding around in a convertible bird dogging chicks and banging beaver.