I was thinking about purchasing these mods- k+n filters, tpi airfoil, performance chip, and slp intake runners- how much power can I expect? ( i know this should have been in power adder, but I am also asking about how much the runners give me)

 

I see no one has replied to this so I'll give it a shot and bring it to the top again at the same time.
These are just guesstimates of course because things do vary from car to car and mods do affect each other.
K&N = 5-10 hp
airfoil= 5-10 hp
chip = varies considerably from application to application. Chips change air/fuel ratio and timing and must be calibrated for each individual combo for best results.
SLP runners = again, probably 5-10 HP, maybe as much as 12-15 on a stock 305. These runners can be ported to get better gains but in original "as cast" condition they are not very high flowing. The Accel long runners might be a better choice for you, or even better AS&M long tubes.

Don't neglect the exhaust system, check out the exhaust board for tips. Headers and/or good catback (not just a muffler) will help nicely.

Nope, it wouldn't belong in power adder. That board is for turbocharging, supercharging and nitrous oxide. This would be the right board for TPI questions.

If you do a quick search using this boards search function (enter words like "airfoil") you can find many posts answered about these basic questions, like the following one:
https://www.thirdgen.org/techbb2/sho...hlight=airfoil

 

I would put headers on before I did the SLP runners or the chip. I don't have them yet, but I still think you'd be better off going with headers and a K&N first.

 

i haven't had my z28 for too long, and i haven't modified it much, but i've been reading a lot about it and i'd say skip the chip and go for exhaust or upgrading the ignition.

 

Headers and High Flow Cat
OR
3.42 Gears