The dash meter was suction cupped to the window, which I call metering at the dash.
Correct "at the dash" is generally what people call 4" up from the dash and 12" over from the A-pillar on the windshield. This is DB Drag style.
Where on the dash do you mount the meter exactly? Windows up or down? A/C on or off? Can you touch the gas pedal? Music or a tone? Visors up or down? Glove box open or closed? Passenger seat reclined or normal position? Passenger seat pushed all the way forward or all the way back? Bluetooth, CD, AM/FM radio, IPOD, or zipdrive? I want to make sure that
"At the dash" means sensor mounted to the windshield 12" over from the A pillar and 4" above the dash. If you're off a couple inches it shouldn't make that much difference. If you go to a dB drag or other show that measures up there the judge has a jig for placement and they'll normally put a little grease paint or sticker there so that they can position meter on subsequent runs and so that you'll have the spot for your own testing.
"Legal" is doors and windows sealed. AC on may or may not gain anything, same with moving around seats, visors, consoles, glove box, etc. Removing seats entirely may or may not be allowed in your org and it also may or may not help your score. I have had it help a little, hurt a little, or make no difference at all. If you started pushing more power it is likely you'd want the seats in place to help keep the cones loaded down a little more. Deadening is typically allowed just about anywhere, at least one layer. Some orgs have limits in front of the B-pillar. Again, deadening is just as likely to lose as gain for you. AFAIK everything except for "music" classes allow test tones, any normal media source (so probably not a tone generator, but USB, bluetooth from phone, CD, or iPod). It is easy enough to find a """song""" with a 3 second test tone in it, in fact most of the old school woofer test CDs would have a track with some techno beat and tones of a known frequency scattered around in the "song". Up in the northeast, rookie/amateur classes used to use music only or music run averaged with a tone run. If you're not using a tone it's worth mentioning "on music" when you report numbers as people will understand your burp number would likely be .2 to .5 higher if you spent a little time finding the right "song". My "music" and burp numbers were only about 2 tenths off when I was doing those rookie classes and that was using the official test CD of that org. I doubt any orgs are still making people use their CD these days because USB/Bluetooth is so common.
Some orgs used to measure engine off, AFAIK most would limit you from revving beyond 2K RPM. That shouldn't make too much difference, and battery tech being what it is today I'm not sure it even matters all so much.
If your org does something unusual vs. dB Drag (which is basically the standard worldwide) it is well worth mentioning it when you mention numbers. This way people who have been around have a proper reference point.
Every vehicles windshield is at a different angle. But kick panels are pretty standard in most vehicles.
The point being that just about every vehicle gains significantly measured at the kick. People who have been around know what vehicles are "friendly" to SPL, but it doesn't matter. Your 148.5 outlaw in your truck is nothing like 148.5 legal and if you care to try to find all these hypothetical gains or even quantify the gains you got for the upgrades you have done you will quickly realize that 148.5 isn't "almost 150". I can't even count how many people fought for years to get from 49 to 50, myself included.
Just go meter dB drag style sealed at the dash and you will see the importance of this distinction. Hell just sit in your passenger seat and bang your favorite bass track then throw open the driver's side door and it will almost certainly be a dramatic difference. Take a little time to test all that other stuff you mentioned and see how much or how little any of that changes everything. You can very probably find 4-5 tenths in there if you took some time testing all those things you mentioned. That said, do not assume that running the AC or closing the vents will gain metered outlaw just because you gain when you test sealed at the dash.
You will gain a new appreciation for numbers you so casually throw around once you try to find them for yourself.
