quick question here... long before all these things... polish, wax... etc etc... does the brand for car wash shampoo/concentrate really matter? I mean... I'm here at Pep Boys right now... and Meguiar has one priced at $5, one at $8 and one at $10... I'm just wondering if they really make that much difference at that stage in the cleaning process? And Pep Boys have their own brand that's like $4 for a whole freakin' gallon!