If you're into German guns, then say no more.
If you want a Kar98k, get the Tanaka. DO NOT get any other. I dont care if you think its cooler cause its slightly more realistic, get the Tanaka. trust me, you will love it!
If you are after the MP44, AGM makes one that lots of people i know enjoy quite a bit. they said it performs really well. ive held and shot it. performs really well stock, and once upgraded, im sure it will be a beast. you should weather it down to make it look cooler.
For the MP40, get either AGM, or SRC. i think the SRC version is better, but that is just my speculation. do some research and let me know what you turn up. id be interested in hearing it.
For the MG34/42, apparently a Chinese company is making one, so wait and see.
Unfortunately for both of us, no company currently makes a G43 or an FG42 (though personally im a G43 whore). Hope that helps. If you want WWII gear, check this out:
Hope that helps!