If you want to avoid headaches, stick with simple mods for now. Once you have funds accumulated, time and space for the swap, then you should go for it. Until then study up and figure out what kind of goals you're going for.
Example... What kind of Hp/Torque are you looking to obtain? How much do you want to spend? Can you devote time and money to accomplish your goal? And like they have said, headaches are normal due to complications. Just be patient and before you know it you'll be on your way to show off your swap on here.
Some options you can go for are: 3sge, 3sgte, 4age, 1mzfe(v6)
Or... If you want to use the 5sfe you can turbo and still get decent power.
If you have troubles finding info look through some swap threads, there's plenty of them.
Good Luck and Post your swap thread!