the AR9280 is AR5B91 on Ebay.
(if u use 10.5 also= it wont work due to driver being apple included in 10.6.3+ so use instead BCM94321MC)
boot with -x UseKernelCache=No
I have an Dell E6520 laptop too. I try to install Lion for hours now.
No matter how I try to install lion (the tutorial from this post, #####, rboot, . . .)
I get this error:
unable to open var db bootcache.playlist 2 no such file or directory
I googled alot but nothing I found helped me.