You're going to put a lot of wear on your engine...especially since you want to run nitrious through it.
First off, if you want to make it a powerful, you have to upgrade your whole rear end. Just for the nitrous alone, you should have forged pistons and hardened rods ATLEAST.
Of course, people will tell you that you can always just throw a charger on and go...but that's foolish. You'll need different fuel injectors and lots of reenforcement to get it to last how you want. It's not an easy task. Also, many superchargers take lots of work to get it to run correctly.
Evaluate what you need this for...is it going to be a race car, or a commuter car? If you're going to use it to get back and forth each day...don't go crazy modding it. Plus, most of the money you invest you won't get back. You don't want to damage the reliability of your car if you need it for school or work. You might want to just save up for a V8 instead. But I don't know what your needs are.
PS...your girlfriend sounds like my dream girl
