I understood the post just fine. The forum is already pretty bilingual with the presence of members from Quebec.
Anyway, from what I can tell from google (I know very little about the 551s from any company), it looks like the cybergun 551 is a rebrand of ICS. At least the regular non-blowback is - I'm finding very little information on the EBB version.
Anyway, if you're going to swap out the motor, I would swap out the gearbox as well, unless it's doing something proprietary for the blowback.