I seen several diesel trucks that have been modded run into the 11s. Those guys had larger turbos, Bully Dog boxes, etc. Kinda funny watching a gazillion pound F350 dulie charging down the 1/4 belching huge plumes of black smoke. Ahhh.. Rednecks and their toys.
If he just has the tune, you should be able to take him rather easily. However, if challenges you to a tractor pull, don't bite.