Suzukipartshouse.com. I would start there for the OEM part number then search for a better price. If it is available they will have it but if it is commonly available they will not be the best price. Some consolation is that it is OEM Suzuki parts and not a knock off.
I don't recognize the flag. Where are you? Morocco?
P.S. He may be having problems because, at least in the US, there was no 2010 1000. The K9 and L1 used the same 12160-47H00 connecting rod. The K9 used the 12111-47H00-0F0 piston, later superseded by 12111-47H10-0F0. The L1 used the later part. It ought to be correct for the L0, if that's what he actually has.