I guess a very brief description of the differences would be that provided in Wikipedia for EQ-6 - new Sherloc digital RWR, new Cyrano IV-SP1 radar, and capable of carrying two Exocet missiles at once. 30 built
Mirage F1EQ-5 is capable of carrying a single Exocet under the fuselage. Other sources indicate Cyrano IV-MR radar with terrain avoidance capability for the EQ-6.
An interesting piece of information on the EQ-6, that I came across, is that back in 1989 those were equipped with rails to carry and launch Kh-29L soviet/russian laser guided A2G missiles.
On a different note, I am happy to see new Mirage F1 variants with later cockpits and more recce, ECM, etc. pods included in the weapons list, so I hope we are close to the moment when it will be time for updated Mirage F1CT/CR versions.