ShootinBlanks

So I took my 07 Silverado NBS 4x4 in to have a dealership perform the Maint II package and to check on my cruise control. At highway speeds if I rolled up the window all the way and the window motor "red lined" it would cut the cruise control off. They fixed that issue but caused another one. After I picked it up and driving off the lot i intantly felt like my truck was handling different. It feels a lot heavier,not as responsive, it seems like the engine is reving higher/worknig harder and by MPH has dropped by 6mph average. Here is what they did according to my invoice:
Engine Control Module Reprogram. Performed TSB #09-08-68-001. Reprogrammed ECM with updated software calibration cruise control condition.
Any ideas?