Differences in DC112a, DC112a zain and DC113a

I have an Unite Explorer 815s. And I was looking for something to boost my cellular signal as well as give me a stronger WiFi signal. So I called Netgear to find out what the differences are between the DC112a, DC112a ZAIN and the Dc113a. And he did not seem confident AT ALL over the phone, but this is what he informed me.

DC112a ZAIN was private label early release of the now DC112a. It was first released on 3\2015. And there is no difference between the two units. But I did have a seller of one saying that he had a newer version of the DC112a and was not the old version. And his was better and faster.
Netgear stated that the DC113a is there newest release and is a faster router. But he could not tell me anymore as to what was different. And the other specs were the engineers secret. I said that was not important to me as the weak link to it was my cellular speed not the router.

Bottom line is that I am trying to boost the cellular signal to my Unite Explore 815a and give a stronger WiFi signal. Trying to avoid have to buy a $600 FULL cellular booster system with an antenna that I would have to mount on the roof of my 5th wheel.

Thanks for your input and factual advice.