To do 110k stable dps as a rogue, I would estimate that you need ilvl ~520+, since I do about 85k solid with my 504 rogue, no matter if I use this CR or play manually.
So, you eighter have a realy good geared rogue, or your friend is lying to you, sorry..
EDIT:
110k dps over 20mil is 181 seconds. So, it doesnt realy count.. 3 minute test is NOT a solid dps! Do atleast 5 minutes to get your solid dps! DPS is calculated with your average damage over time, so if you started of with a realy high burst, like rogues do now, then the average has not been actually averaged out, its still dropping from the big burst.
EDIT2:
Go to
ShadowCraft - Rogue DPS Spreadsheet, enter your realm, character name and zone, press Begin, then tell me what the number of your theoretical dps is on the right side of the window. Then I can tell you what you should be having as an average with this CR.