Well, first off, I would like add some exhuast, I am wondering what type of effect it will have on it, and what is the best to use, I am close to 60K miles, and I am about to change my plugs, can anybody recommend any good ones?

 

And it is a 2004 truck...silverado of course, reg cab short bed.

 

I had an 04 4.3 reg cab sht bed, and was basically told (by my brother who's a shop manager at a GM dealership, and my father who used to race funny cars) that an exhaust system would do basically nothing in regards to horsepower in the grand scheme of things, adding an exhuast system t a 215 hp engine isnt going to make it a whole lot faster, if its just for show/sound thenI have no idea.