Regarding the 4G LTE mPCIe cards found in "http://wiki.mikrotik.com/wiki/Supported ... and_modems"

If you install a 4G card using the LTE interface, does it imply you have automatic support for Direct-IP or are those things totally unrelated?

Regarding cards with possible built-in NAT (didn't know it existed until I read about it in the forum):
- Is it common that 4G cards utilizes some kind of built in NAT?
- will Direct-IP bypass any possible built-in NAT-function in the card?
- are there any particular 4G cards you should avoid if you don't want to have built in NAT?