At AutoZone,the gumout products are in bigger bottles.walmart advance auto sells them much smaller containers.yet directions the same.high mileage 18 gallons.all in one 25 gallons. Are they the same big and all bottles? Huge price differences too.think it's good use highileage everything? Not including cost..including piston tops clean .worth it?I use Lucas ucl. I'm Gunna use it for a while, and next plug wire change get a borescope in. GM 3.8 v 6. Wires notorious for breaking n melting ..so Gunna wait till it's time.