Question Amp+Speakers

[wsnnwa]

So I have a weird situation and I do not know much about how this will work out if I go ahead and do what I plan on doing.

I own two GEMINI GSM-3622, each has two 18" speakers at 16ohm and 250watts RMS and they are connected in parallel thus bringing the ohm down to 8 once it goes to the amp. Well on each of them one of those speakers died, leaving me with only one speaker on each. I got two replacements(peavey 1801 black widow) from an uncle of mine the ones I got are the same size 18" but they are 8ohms, and at 350watts RMS. So this means that once I put them in to replace the old ones and connect them in parallel the ohm would be 5.333. I will be connecting the pair to a new Behringer EP4000, 2 x 2,000 Watts into 2 Ohms; 2 x 1,400 Watts into 4 Ohms; 4,000 Watts into 4 Ohms (bridge mode).

Would everything be fine? Should I instead put the two peavey 1801 black widow's together in one box and the other two that have the same specs in their own? To keep one at 4 ohms and the other at 8 ohms, would these be better on the amp and speakers than what I had originally planned.