What modifications can I make to my new '05 F-150 5.4 XLT that require no expensive aftermarket parts to increase HP, torque, etc. I've allready bought the K&N. Any suggestions would be appreciated.

 

This forum has a good Search feature that will help you find unlimited things to modify on your truck to get more performance. The most popular, easiest to do, modification is to get a tuner. Under $500 and it really does make a difference. Here's a link to information on one of the most popular ones right now.
http://www.sctflash.com/

 

truckB...norman's advice is sound. More bang for the buck with a tuner. You'll probably get other suggestions (e.g. gears, pulleys, etc.), but individually each mod won't offer any significant performance enhancement. The issue here is trying to hustle 5,600 of iron and odd bits down the road...a formidable task if $$ is in short supply. Keep your expectations realistic.

 

Truckbastard, what is your idea of inexpensive? If you're looking to increase HP and torque you will probably need to spend a few hundred dollars, minimum.