This is incorrect for the 2009 model year and up. Arctic Cat changed the rear of the tunnel to be shorter with more taper, aluminum bumper, and flat cooler.
I put a 3" lug 162 Powerclaw on a 2009 M1000 162 that had originally had the 2.25" lug Powerclaw. I haven't felt it while riding, but the track lugs have rubbed on the rear tunnel cap enough that it's scuffing them up a bit. Tried increasing rear shock pressure to lessen contact during bottom out, but then it washed out worse on sidehills. So given this experience I would recommend extending your tunnel.
Even with the 2005-2008 rear bumper and cooler setup it doesn't work to lengthen the track and keep the stock shorter tunnel. I lengthened my 2005 M7 from 153 to 162 and left the tunnel stock to try it for a ride. The paddles rubbed the curved cooler that hangs down in the back pretty hard anytime I bottomed out. Either on the trail or just going through a sharp V ravine or creek. Ended up putting a different bumper tunnel extension on from Van Amberg to fix the issue.