I'm not a CAI hater. I ran one on my 06 F-150 (Volant). It made great noises, but nothing performance wise. I finally strapped a blower on there for real giddy-up
I ran one on my 09 Mustang Bullitt...now that was good for +15 HP with factory tune...and over 30 RWHP paired with long tubes and full offroad exhaust.
You are only going to see 3-5 HP on a good day from a CAI on a 6,000 lbs vehicle. Tuning might get you closer to 10 HP gain.
As far as tuning, most of the "Custom" tunes you buy are canned. The tuner takes a know profile that makes good power, tweaks it to your octane and location and sends it to you. I've had great success with those using my Mustang because a dyno wasn't available where I live
Once you have the tune installed, you can data log. Send that back to the tuner and they can tweak things in to give you a truly custom tune
It was only 215 bucks and it sounds like a beast. I'm hapyy with that. Any advice on a exhaust or an aftermarket MAF? Who should I talk to at sct? Finally, can I get a tune for 87 octane? I don't really need to spend more on gas...thanks!
Its probably where the intake comes in through the "cold air" shield. Mine rattled there. The fix I made was to get some black fuel line hose and split it length wise and put it around the opening where the plastic air line connects to the filter. If this isn't it, make sure all your radiator clamps are tight. Drive for a while and then check for shiny spots where something is vibrating against. Or with the engine running and the hood open, pull your throttle cable and see if you can pin point the rattle.
Hope this helps, PM me or I'll check back if this works for you. Otherwise my late night coffee induced rambling should get a picture to help say what my words may be missing.
Is the rest of your truck stock? Exhaust? The funky shape of the OEM intake is because it stops odd harmonics similar to what you are hearing. The K and N is more than likely creating resonance and that is vibrating the dash plastic. The dash is known for rattles, etc. If you can recreate the rattle without blowing up your engine while parked you might be able to locate it and then add foam/felt tape/etc. to eliminate it.