Dell XPS 15 R2 - L502x dimmer B+RG display

Hello,
I apologize for posting what perhaps was covered before - like many weak-minded, I faint easily in front of endless oceans of information...

My problem. When I got a Dell XPS 15 R2 - L502x, I was really blown away. Amazing computer, the like I've never had before. Nevertheless, for some irrelevant reasons I had to exchange it. The replacement that I received was fine except the display. The B+RG makes it's colors very vibrant, although the overall picture is dimmer, with this yellowish, greenish hue, especially noticeable when viewed against a white background. It is easily distinguished when compared to the original computer when side by side. The best way to describe this would be: (And I know it doesn't exactly work like that, but still, for the sake of the argument) the computer no. 1 has a B+RG WLED and the computer no. 2 B+RG (regular)LED. The settings are identical, the levels are maxed out. I called Dell and spent hours trying to figure out the problem to no avail. The make and the model of the displays are the same: AU Optronics KYYVK. I got the first computer on Apr. 15, and the replacement on May 9th if this helps.

Also, I tried to exchange the hard drive and couldn't. I followed the instructions and everything: took out the battery, unscrewed the one screw and tried to open the palm rest cover. But without causing damage to it, it felt like it wouldn't open... Any special tools I need to use or something?

Again, I apologize for the long post, but would really appreciate any help, since I don't really know where else to look for it.

Thank you.