Hello everyone, just purchased a new 2009 dodge 2500 qc sb 4x4 6.7 cummins and wanted to know a couple of things :

1)what mods are ok without voiding the warranty (i've done cai and mbrp 4" exhaust w/o muffler)
2) what are the largest tires that will fit on a stock truck (with the big horn package)
3)any programmers available for late 2009 trucks

Thanks for your help