2003 Acura RSX has less power

Stop replacing parts without performing testing, that's the first thing! First, did you use Acura plugs and wires? If not, you may not have the best results for your performance. Additionally, is there a check engine warning light illuminated? if not, there may be nothing wrong with engine performance and perhaps your transmission may have a concern. It's impossible to diagnose via guesswork. You'll waste a ton of money and risk making matters worse by replacing good parts with substandard ones.