Throttle Body and Plenum?
 

Is it worth the$300-$500 they cost? Does anything else have to be changed after putting them on? (as in fuel ration etc)

they are def worth getting...tho alot of ppl on here say to buy them used because their overpriced new. i bought mine new anyway though i dont like used stuff.

Dont spend more than $300..... you can get used but I can also find combos that are right at $300 new

I spent like 400 on my new Accufab 75mm tb and plenum, they're great to have if you're doing bolt ons. They will change your a/f ratio because it can allow more air in.. but it shouldn't be too dramatic.