Just my .02c on this...
and just to correct some misunderstandings here.
You senior members here have heard me say this before, so, go get a fresh beer while I'm talking to the younger/newer owners, K?
A true "cold air induction kit" is one that sucks, scoops, or collects cold air from outside the engine bay and ports it to the intake. Therefore, the ONLY cold air inductions systems presently available to us are 1) our own OEM air box as it comes from the factory, which sucks cold air from behind the driver's side headlight pod, and 2) the '03 Mach I hood scoop kit from
www.KarKraft.com which ports cold outside air into the internal air box where it's filtered before ingestion. BTW, this Mach 1 kit requires major mods to the hood and air box, and as far as I know, no one has undertaken converting it for our use, so, nevermind this kit, eh? The remaining kits/filters mentioned here, do not import any cold, or, fresh air from outside the engine bay period. Therefore, the "best cold air induction kit" remains our OEM air induction system due to its source of fresh, cold air...IMHO. Let me explain more?
Metco's offering is a spiffy attachment to the OEM air box, and it's really slick too. It traces the visual appearance of Kenny Brown's carbon fiber "bellows" (which is not available in kit form) and it's sweet, cheap, (umm...Inexpensive), and just plain looks cool. Some may accuse you of being supercharged, so, be honest if challenged, eh?
However, Metco's kit disappoints me, and only because it retains the OEM air box that still relies on the small fresh air source from behind the headlight pod. I say "disappointing" only because this kit does not attempt to capture any more fresh, or, cold air than the OEM air box already provides. It will smooth the air path to the intake, yes. But, it makes no improvement on the OEM source. Damnit too, I was hoping for more fresh/cold air from this kit.
Paul's kit (and most likely K&Ns kit will too, if we ever see that) removes the OEM air box entirely, taking it's fresh air (however limited this is) collection with it. Paul's kit replaces that with a K&N style conical air filter that sucks air from inside the engine bay. Yes, it has a heat shield that allows you to target the air path you wish to sample from, but it's hotter engine bay air mixing in. Any cooler air blown in from below the car gets mixed with the hot air blown through the radiator, trans cooler and so on before it's available to the kit. Any cooler air still filtering to it from behind the headlight pod is likewise mixed inside the filter. Therefore, it sucks more air, but that air doesn't stay much cooler, and I believe cooler is the factor we should be seeking...IMHO. So, while Paul's kit is likewise visually impressive, it's not improving the quality of air we get from the OEM air box. This is likewise disappointing, as an "upgrade" to our OEM air supply.
Well, seems none of us want to mod our MMs with a General Motors cowl induction thingy, so that's out. None of us seem excited to add a Mach I hood scoop either. Until we explore more options, there isn't much to choose from right now.
Until someone designs a way of collecting cold air from outside the car with a forward facing scoop of some design that collects from the forward movement of the car, we should not expect any outstanding performance gains.
IMHO...The OEM setup is still your best option. It's on the job, but it's handicapped. I looked at several pics from the Indy event, and noticed several members understand what I've explained here before, because they "raced one-eyed." Bravo! Someone is listening.
We need a scoop somewhere on the front of the car, that ducts to the OEM air box. This would show a major change in performance regardless of what follows in the induction path. On that note, for those of you who posted here about improving the OEM filter alone, remember this?
The tighter the filtering process, the less air processed. The looser the filtering process, the more air processed. Watch your "micron" count, because higher numbers mean tighter filtering, and less air processed to the MAF and intake. I'll save my discussion on this point for another time.
For the record here, my MM is supercharged and not suffering from these concerns. Yet, I remember my first N/A MM, and my concerns back then. On behalf of the new Mm owners here and asking questions, I'm just looking for the best mod for the N/A MM again. I do not support any particular vendor, or, train of thought on this topic, no bias in any direction, eh?
I use a K&N conical filter on my Kenny Brown car, and rather than oil it, or, clean it, I replace it with a fresh filter once it's sufficiently used. This works for me, because N/A or supercharged, the best filter is the clean filter. If you're really a performance minded owner, this cost goes with that program.
Thanks for listening, I'm
sergntmac@aol.com for rebuttals.
, sure, that would look cool... Maybe down the road, not real big on cutting up my new hood.
is that true ? 
