The CAI and tune would be my first options, but obviously not if the end game was FI, as I see you are going. The SB is pricey, especially for what it does, but no one else makes one and they really do improve throttle response.

I first was a non-believer and Tom lent me his to use while his car was in winter storage, I was hooked and didn;t want to give it back. It was an older style, single setting, always on model. The adjustable is great, anyone who has feeling in their body can tell the difference between on and the first setting, much less the last two. One caveat, Max sold his because he was going through gas much quicker because it was more fun, that does not bother me as I believe it is what you are supposed to do with a pseudo-sports car

I love burning gas...