I'll take this one
Hookers and coke is the top response.
There are many other places you can make gains for less money. This is best left to the very serious and/or very knowledgeable.
It seals the snorkel to the bonnet and makes sure all the air goes into the snorkel. Clark Rubber (for instance) has suitable foam if you want to replace it.
Stock fuel rail and injectors $40 also have bare rails for cheap (just make an offer on them)
Coil pack cover $30
Rubber intake $15 (perfect condition)