A good set of spark plugs

I have a 02 4x4 Silverado w/5.3L and was wondering there are any plugs out there that any one has tried that work especially well. I have heard that I should stick with the stock plugs, but I was thinking that if I used a higher quality or more accuratly a more efficient plug that the truck computer would be able to tell and might advance the spark timing to help achive better mileage and power, while reducing any knocking, or predetination (not that I'm havine any problems). I admit that I have no idea what I'm talking about, so with that said am I way off base here, am I thinking too hard about this. Please tell me if this makes sense or if I'm just fighting windmills here. Oh, if it makes any difference I have made the following mods to my truck, K&N FIPK III, Magniflow exaust system, Edelbroch headers, and a soon to be utilized Hypertech Power Programmer III.

stay wil stock plugs and your knock is probably piston slap

When does it make this knocking sound is it a start up or while driving? Stock plugs are definately the way to go.

I agree about the stock plugs, my 2002 Z71 is also having piston slap stuff, and I can tell you that you cant fix that with new plugs; im not sure how you can though...