The smaller displacement reduces average power across the range relative to the 3.0L version, and both engines are relatively torque shy.

"More power" usually refers to higher peak power, and any modifications to increase peak power usually reduces low end torque/power, which is not the way to go on an engine that is already torque shy.

"High performance exhaust systems" and filter on a stick inlet systems will do little, but increase induction and exhaust noise. The OE inlet and exhaust systems are both very efficient.

Beyond this there are few "performance parts" available for these engines, and those that are available are expensive and will essentially require an engine teardown to install. The quickest and cheapest path to more power, would probably be the installation of a used 3.0 engine that you could acquire from a salvage yard.

The least expensive modification you might be able to make is first gear start for the transmission, and this has been discussed on this forum.

Keep in mind that these engines perform best in the range of 5000 to the rev limiter, which is about 6650, but varies slightly with model year. The engine is very robust and will not be harmed by using the upper reaches of the rev range when required for maximum acceleration performance.

Duke