what is the cheapest mod that will add the most horsepower to a 98 cavalier 2.2???

umm u cant say cheapest mod and most horsepower together, just doesnt work. You want alot of horsepower you spend alot of money. You want a little horse power you spend little money. For cheap the most HP you will prolly gain with an upgrade is 5-10HP.

how much are you willing to spend?
yea if you want to spend a couple hundred you can get a nitrous kit. or for a little more or alot more you can get a turbo kit. but that's kinda expensive. so if you want cheap mods go with a cai (cool air induction) exhaust and crap like that. they dont realy do much but if thats what your looking for there's your answer. but dont expect any real noticeable differnces. like jayson said. no big gains from those.