that meter is a pos. unless your system cant hit over 126dbs...//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif wich im sure some factory systems should be able to do that on that analog mic.
termlab is one of the best and cheapest if you got your own computer i think their like 599$ plus shipping. well well well worth the money.
but if you just want to see how loud your ride is just find someone with one like me LOL and ask them to meter your car. some might do it free some maybe charge 20$ an hour or so.
but to me i think the termlab and ac 190 are the most accurate and best mic out their.