Never tried the Dark Core RGB (I assume you are asking this because you own other Corsair products and want to sync them) but if you don't mid not having a wireless mouse out of the two I have tried and own (M65 Pro RGB FPS and the Glaive RGB). If you need a sniper button (reduces sensitivity for increased sniping accuracy) then Corsair as far as I know has only made 3 mice (not including new versions of each mouse and not including mice such as Scimitar Pro as in software you can assign a sniper button to it) with a sniper button.
1) The M95 was the precursor to the Scimitar and I really liked it but as it wasn't updated the sensor is outdated and it has a blue LED logo which isn't RGB and I don't want a blue LED.
2) The M65 is the most basic mouse from Corsair with a sniper button it has a forward and back button as well as DPI up/down buttons.
3) Dark Core RGB which you said you already looked in to (I don't own this or haven't tried this)