Get a split port swap kit instead. There are companies out there that sell complete packages for $500-700, they should include the heads, intake manifold, fuel rails, computer, and wiring harness. Those are the components I know need to be swapped out, and as a bonus, you'll make more power with your old cam then a 99-03 engine.
The power difference with the older cam is small - probably 5-10 hp total (if not less). Even though it's better than the newer cam, it's not exactly an aggressive grind.