hey guys, I know these 2 topics have been beat to death, but in my search I couldnt find much information on my specific truck, the 03 Silverado with a 5.3L V8. I currently have a thrush exhaust on it was a downturn right before the rear axle, and thats really the only mod to it (other than audio stuff). I am looking to get better mpg over performance at this point, just because most of my driving is around town and I would rather not be getting killed at the pump as much. So my questions are this: What is the cheapest tuner out there that is actually worth buying? and Is it worth buying a drop-in K&N (or similar brand) filter for my specific model, or would I need to buy a full CAI system for it? And one more... Would my MPG improve with a tonneau cover? Thanks guys!