Um, all YJ 2.5L's are EFI. Earlier ones are TBI though. Personally, I found no gain what so ever when I removed those so called restrictors. The one in the airbox is more of a venturi which causes a vacuum that pulls the crank case fumes back into the engine.

Cat-back exhaust, headers, K&N conical filter, +8mm spark plug wires... Lots of stuff to consider. But you won't be able to do a 4.0L TB since you have TBI. You might be able to do a .450 duration cam. Hard to find the .440's anymore.