Benz C6 vs Vxdiag C6 vs Xentry Connect C5 vs SDconnect C4

Look here: Mercedes Benz Star diagnostic tool: C4 vs C5 vs C6

In summary,

SD connect C4 = SD C5

VXDIAG C6 = Benz C6

All can work for Mercedes-Benz diagnosis, SCN coding, flashing and programming.

But with, Allscanner VXDIAG C6 and Benz C6, you have no luck with HHT for the old Mercedes and cannot access to the engineering software (DTS and Vediamo)