Antifreeze Pentosin or OEM Honda

VW G12 and Pentosin G001200 are the same thing, both are pink/violet in color, phostphate, nitrite, and amine free. You should not mix cheapy prestone / o'reilys with the G12, it may turn the coolant to a sludgy substance and clog the system. Basically solidifies when mixed with other coolants. Also may build up rust or other small deposits through your cooling system.

Regarding genuine VW antifreeze and generic...from what I understand, anitfreeze like Prestone is phosphate free but the real VW antifreeze (Pentosin) also has protectants for the plastic parts of the system, etc. The genuine stuff really isn't that expensive from the dealer.