UPDATE:
I just got the card and upgraded and I didn't run or install anything, so far so good. Connecting to the N 5G network on my router, and the 2.4ghz G band on the same router. Connecting at 130 on the N 5g and 54 on the 2.4 G band. Need to experiment how to get 270/300. I am using WPA2, so I don't know what it will take.
2nd Update:
I am only getting 130 because I set my 5g N radio to regular not wide a few months ago (and forgot). It seems to keep more stable connections. Heck, 130 should work as it has for me in the past. Beats the pants off 54!