The 16" will fit under a stock 2009 tunnel. Rode with one last week. 1/8" clearance per side but it was definitely there.I dont think you can fit a 16 wide under a stock tunnel. I know you can under a cr tunnel but it is lots of work.
horrible track!! and only 15 wide not 16... Tracks so bad that when we were doing tunnels we just cut them off two nytro with zip disks to get them out of the way!!!