iv been looking for a while, and here is what i have found,
you already have a "cold air intake" on your truck from the factory, but imho the K&n intake will flow more air into your truck. and that helps,
the exhaust didnt do alot, by its self but help, the other stuff, as you make more HP you have to get rid of it some how, dont go larger then 2.5'' or you can get into savaging issues.
i went to an efan, it didnt make horse power, but it will free up parasitic loss,
i also put under drive pullies, crank and alt, best $130 i ever spent. again frees up parasitic loss.
they dont makes cams that i have found thats not a reground. how ever, you have 1.6 rockers (i believe rolling type) the 1.7 rolling rocker, will act like a new cam, and will hold your valves open longer,
as far as the jet chip, i think its bs, if you read the small print, you have to have different things done to your truck for it to work. soo what if you have more, it wont compensate for it. but tuning is a good thing, but that it to a shop, have it dyno tuned.
tb mods and maf mods are good and cheepish or free.
the best way to look at it, the path thur the motor from air filter- tail pipe is always the same. upgrade one part at a time. and figure in the cost to benefit ratio. ie a 9'' cold air, ram air intake is pointless on a 1'' tb. as i see it the "air" part of the air fuel spark has the biggest mod base.
you have the intake, maf the tb, p and p, rolling rockers. and a spark plug hasnt even fired yet.
just my 2 cents