1.) It works if you build from lastet souce (see http://linuxwireless.org/) and then remove /etc/modprobe.d/intel-5300-iwlagn-disable11n.conf
2.) There seems to be a bug in the lastest source so do NOT use the driver-select script.
3.) The driver might still have some minor performance degradations compared to 10.04.
I reported this upstream http:// bugzilla. intellinuxwirel ess.org/ show_bug. cgi?id= 2260.
I then I had a *lengthy* discussion on #linux-wireless on IRC.
To summ it up for you:
1.) It works if you build from lastet souce (see http:// linuxwireless. org/) and then remove /etc/modprobe. d/intel- 5300-iwlagn- disable11n. conf
2.) There seems to be a bug in the lastest source so do NOT use the driver-select script.
3.) The driver might still have some minor performance degradations compared to 10.04.
I hope this information helps you. :)