The management you use really doesn't have any effect on what power you make, unless there is a problem with your install and you end up curing that by proxy, I would at least get it mapped/setup by someone reputable like MSD (or whoever is close to you) before changing, if you do have issues they may well be able to sort those there and then too.

Fitting a nice new ECU and loom is always good and often comes with many new features, but may well not be needed in your case