Depends on what "best" means to you:
- lowest parts cost ?
- easiest installation ?
- compatibility with other mods (e.g., NOS and/or forced induction) ?
- cool looks ?
- cool sound ?
IMO the performance gains with an intake are pretty minor, unless coupled with other mods (e.g., headers, exhaust, chip, etc). Non-cold air units may actually degrade performance.
If you want to try something, put an aftermarket filter (K&N or Uni) into the stock airbox, and get an ehanced sound... quick and cheap... the tab goes up from there.