The different numbers are region numbers. USA uses 1 and the end of the model number. while other countries use other numbers. Read the DMS4 EZI thread in the modchip forum here. Its gives info. Also there is a modchip thread there too about various chips. You might want a installer since ps2s can be tricky though v7 seems to be the easiest. You should be able to find a nice unit. Hope this helps.
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