yea... loaning money to mod your car's really not smart. think about it, you're paying interest on a loan, but you will get no money back from modding your car. my suggestion is to hold off until you have the cash to pay for the mods. i'm not trying to be mean and i'm not trying to burst your bubble, but its really a bad idea.
the only loan i'd use to mod my car would be on the equity from a house. lower interest in comparison to other loans...

 

Like previously stated, if you don't have the $$$ don't take out a loan or use credit cards. This is how you will get yourself in debt at a young age. And trust me I did the stupid mistake of maxing out my first credit card while I was in college, I think it only took a week.