I have a Dell Precision M6800 workstation Laptop. It is older, but still an excellent functional laptop for use in our organization. What I would like to do is upgrade the older Intel Centrino N-6300 wireless card it has. I normally don't have trouble but this time I am having difficulty finding what wireless AC card is compatible. I saw the AC-7260 but I was wondering if there was a better card? Also the current card has 3 antenna cables connected to it but all these cards I look at have 2. Which 2 cables would I use? There are black, light gray and dark gray. Any thoughts or suggestions would be appreciated. I really appreciate it.