I started first by switching out the spark plugs to E3's. I noticed more acceleration and quicker response afterwards. Then I had the secondary muffler removed before having a DC aftermarket muffler installed in place of the factory muffler. Both parts I bought at AutoZone.
My next project is to replace the factory intake and air box with a K&N Blackhawk Cold Air Induction. Eventually I will add a Turbocharger and Intercooler.
Don't know if this reply helped you any.