I recently purchased a 2003 GMC w/ a 5.3 V8. I am looking for ways to really open this thing up. I am wanting to put a mild cam, a cold air intake, and a programmer on it. What is the best route to take and most economical? ............Thanks in advance for your input

 

the sky's (and good 'ole $$$) is the limit. See sig for my mods. it really woke mine up. good tune, exhaust, cam, headers, and stall and your good.

 

I would start with the intake and then exhaust just to get it breathing better and use like a Superchips programmer maybe to tune it up a bit. That is pretty mild and economical, you will see some good performance out of that and better MPG. Anything after that is kinda out of my realm of expertise. I hope someone else can help you out better if your looking for more.