2 Cobra tops and 2 Cobra subs/side is your basic Cobra 2 rig. The only possible difference would be whether or not the subs are the "long throw" version.
A true Cobra 4 rig uses more and more specialized boxes, especially in the subbage with 8 long throw boxes as standard.
Not your QRX stand-in........
I'm saying just saying that I have put my QRx/SRX rig in he same rooms (ballrooms & churches) as him and been able to provide great sound for the Client. I have put my rig in a warehouse for 500 people at a GoGo event and lived (IT8000 can trip a 20amp break with 2 4ohm loads)
The guy who owns the rig does have Top & Far boxes for a complete Cobra4 rig. I believe the "Top" among the Cobra2 & Cobra4 are the same boxes. The Cobra4 has the "Far" box for the throw.
The set-up for the rigs I've mixed on was (per side):
Cobra: 1-Far, 2-Tops, 4-Subs & 1 amp rack
KF: 2 KF850, 3 SB850 (total: 1 top rack, 1 sub rack)
I preferred the 850 rig over the Cobra-Set-up. This was a field show and I used my LS9 at front of house.