my motor just got put in and ive been searching some stuff and not sure wut to do first...i was on ebay and saw all these stupid performance chips for sale and all of them are different sellers and all says adds 20 hp...is it for reals? if it is does it work for my 93 Ka24de?

i was looking at exhausts...wut should i get that would sound good and not riced at all...i dont want something thats screaming, i wanted to get something with a somewhat deep sound to it...like a sti. wut should i get?