I've done a few cold air intakes on various cars/engines, and believe they are one of those modifications that if done right, that is, to actually grab cooler air than the factory air box was getting, there may be a slight improvement, maybe not enough to even feel. One cold air intake I did came with a larger pipe that the MAF sensor screwed into so I had to re-figure the MAF curve. It ended up being about 25% change than the old MAF curve, but then the new pipe was about 25% bigger diameter so that made sense. In the end, I think it can't hurt to do a CAI, if you do it right, but it may not help a whole lot either. Maybe on a dyno, or running the quarter, you may be able to see "some" increase, but not really enough to make a big change in the way the engine feels when you drive it. I suppose if the factory intake set up was really restrictive, then you could notice more. Some CAI kits come with a tune you need to load as well. I always wondered how much of the increase is from the cold air itself, and how much is from the tune?