Welcome to the Community. I would suggest you call Dell Tech support while replacing the WWAN card, so while adding the card incase you break a part, they will replace it for you, since you were on the phone with them. Also have them update your video driver, for the flikering issue, or you can update it using the below link.
<ADMIN NOTE: Broken link has been removed from this post by Dell>
its been about 6 months since i first posted this topic, but i called dell support to fix this issue, the sent an engineer to my house, he spent about 3 hours and replaced the lcd, after he left the laptop wouldnt switch on, so i got dell to take it for a repair, i got it bak 2 weeks later and they had messed a few other parts up and the screen would just go blank after every 5 mins. And it was still flickering. so i called them again and they took it bak again and repaired it. just got it back yesterday and it still has exactly the same problem. screen is still flickering on the lowest brightness. ive called them and they said theyll have to book an engineer to have a look at it. But im assuming they dont really have a fix for it since theyve replaced the lcd and so many other parts in the laptop.
also does anyone else have this same issue, if you could please check by setting your screen to the lowest brightness and let me know, then at least ill know its not my eyes