All you need to unleash the power of your Thunderbird are three things!
1- Cold Air Intake 2003-2005 also for 2002
2- Exhaust 2003-2004-2005 ( says 2003 but will fit 2004 & 2005 per this post. 2002 only fits 02 model.
Also recommend replacing ignition coils since these are often bad! They are...