Hey ghost,
I too used to live in California, and am moving back soon. I would suggest starting out with the basic RAM air intake (not cold air because water could get in there unless you buy a bypass valve), and a nice 2.5 inch exhaust front to back, with a cali legal cat. That should get the air moving through your d15a1 engine quite well. as far as tools, maybe just go with a basic tool set with metric and standard to begin with. From here, youre on your own, but just remember when lookin for a little power, Nitrous is like a hooker, you hit it a couple times, and you have to pay again. Peace.