here's a mod: put the bottom half of your airbox back on, pull out the intake resonator, get a piece of dryer ducting and a hose clamp, clamp the dryer ducting to the airbox inlet, and run the ducting down through the hole under the airbox and into the bumper. DIY CAI... doesn't do much, but it does something--matched with a K&N drop in filter, thats a pretty good cheap-ass mod.

As for suspension, if you're looking to go for really cheap, don't bother. If youre looking to spend a few hundred, get H&R or Eibach or Neuspeed springs, and some OK shocks--kyb or tokico is a good bet. You can probably find the springs used somewhere, but its a good idea to buy the shocks new.