I knew a kid in high school who didn't know jack about car audio, but he had $$$, and basically told a car shop in town he wanted to compete, and although he didn't know jack, he dropped money at a real shop, and, while not in the 150's, he was high 140's without a drop of car audio knowledge.
He had a ford explorer, with three 15" L7's, each with their own battery and MA Audio 4000w amp. They obviously knew he didn't know crap, since he was running all 3 amps @ 14v, and @ 2 ohms, so he bought 3 4000w amps for ~1200w rms per sub.... But regardless, he hit good numbers.
As long as you have $$$, the only important knowledge you need is the location of a reputable shop, and to steer clear of best buy or circuit city.
It happens.