I would be interested in knowing how you verified the 130M connection to the Xbox 360 Slim. I have the Dir-825 and another N router and have never been able to get more then 65M out of my kids Xbox 360 Slim. The radio in the Xbox 360 slim appears to be DEAF. My laptop (New Acer, purchased last weekend) connects regularly at 270M to the same 2 routers at further distances then the Xbox. I also have several other computers that have 130M adapters and they also have no problem with either router at 130M, once the distance increases the speeds do drop fairly quickly. And what ever you do, DO NOT enable short GI to squeeze a little more out of the router, the Xbox 360 Slim will fight you 7 ways from Sunday.
It has been a few weeks, I don't remember if the Xbox slim software reports speed or just bars. If you were using the routers speed reporting, the older firmware may have been wrong.
Ever since this Xbox slim has come into to my house, it has used every ounce of knowledge I have to keep it running reliably on "N" mode, when everything else just connects. I am even considering disabling the WiFi in the Xbox and getting the kid a bridge. Since I can walk in with a brand new laptop and connect at 270M without even trying(the look on my face had to have been pure amazement), and it has been nothing but a war with the Xbox, I am very interested in any of you findings.
The Xbox has went from being in the same room with my router to 30 feet away with a higher powered router, still only 65M on both firmware versions 2.05 and 2.06.
Even when I was running a Linksys Wap 54G router at 10 feet, the Xbox Slim still had problems and would only connect at 26M. Honestly, I would love to put the Xbox Slim in my skeet launcher.........