I have plenty of room left, could go with a 2.5 if I wanted to. The front of the tunnel is the same on the cf as a m-series. When I extended my cf I left the stock front portion on and just changed the rear to a stock m 162 tunnel. I also used the drop brackets from a m-series. I could see a issue with the clearance if you used the stock cf brackets for that tall of a lug, but I know a 2" will clear just fine with the stock cf brackets.