I was launching in 4x4 and after the 1-2 shift switching to 2wd. Never had a problem going back into 2wd doing this (haven't tried with the Procharger yet, not sure if I want to)

With my truck just having a K&N air filter in the stock box and replacing the intake tube, a free flowing muffler and a custom tune using HP tuner my best time was 14.1 so looks like you are in the ballpark of what I would expect.

Are you launching in 4x4 and keeping it there for the whole run?

 

I launch mine in 4x4 and then put it in 2wd right after I leave te line (before going into second). I've never had a problem with this either