You should be taking your sum of money to a shop. Period. If you can't time a KA properly, then I don't think swaps without explicit documentation are going to end well.

Not sure on tuning. I think you're looking at a standalone to start with. And not a cheap one either. Actually, the AEM2 is being designed around the 2JZ because of the original AEM's shortcomings. So you're looking at Haltech E11v2 / Plat, or better. Sequential fuel and spart on a 6-cyl isn't cheap.

For power, that's well documented.