Default EFS folder

Hi friends , whenever I enter more into the world of android!
I wanted to tell you that BEFORE you flash CM11 did a backup with CWM on the stock rom and it's on the PC! And then flashee SIN CM11 to backup Folder " EFS "
CM11 Now I can receive calls , messages, etc. ..
But I did not copy the folder " EFS "
This means that the flash CM11 Folder " EFS " can not change it?
Currently I backup the folder " EFS " on PC , but the copy is from CM11
My questions:
1 - . Upon backup with CWM also made ​​a copy of the folder " EFS "? So I can restore it and make a copy of the folder " EFS " from the stock rom ..
. 2 - A while ago I went unexpectedly Wifi ! I had to restart the phone and went back to have Wifi ! This has to do something with the folder " EFS "? I had never been the internet as now ..
. 3 - My IMEI on the device -> status - > empiesa with 35 and ends with 60 ( idk if they serve but just in case I tell xD)

I hope to answer soon and get me these questions , I have nerves and I no longer do. Thank you very much in advance!