Hi Aboulaly,
You might find a supplier who provides that service, but its easier and more common to buy a new unit and send it to a modder, then you know whats been done and how old the unit is. BTW your warranty will be stuffed, so it may be better sense to buy a used one and mod it.
There are modders who sell used modded units as well and this is common too.
Cheers
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