IMO I think you should take it one step at a time. Being as you already have the performer I think you would be wasting money at this point on the RPM.
Get your current combo dialed in before you make any other changes. I'll tell you from experience that you can waste a lot of time and money looking for that next 5 hp.
Spend the money on a dyno session with an experienced dyno operator and you'll be wiser and happier. You'd be surprised at how much HP you can find on a dyno. I've seen cars pick up as much as 50+ hp at the wheels with tuning alone not to mention improved driveability and mileage. Just my 2 cents.