I think it's a Mitsubishi turbocharger. In the catalogue I found two numbers (MFD) of turbo from Megane III RS: 1: 49377-07325 this is a turbo with 15T billet. 2: 49377-08380 but this number can't decrypt, no information anywhere what kind of billet there is... Maybe some ovner of the later version (2011 +) of 265 can help me and check the turbine numbers in his car???
All turbochargers in Megane 250/265 are Mitsubishi TD04L6 (15T in first years of production, later change it to 16T). Garrett make turbos for diesels version