04-07 chevy/gmc crew cab driveshaft problems help needed

Ok guys I bought my 05 sierra crew cab about a year ago I have a 5.3 with a wheatley tune on it I slammed it with a 4/6 about a month ago... but as everything was going according to plan I noticed that my driveshaft would start to vibrate at 100 mph I would love the advice many people consider replacing the single piece driveshaft with a two piece drive shaft but I would love advice before actually doing something to fix the problem

have u checked the pinion angle?

i heard these drive shafts were not that stable at speeds over 100mph. it never had this problem before doing the drop? if so then yeah, i would check then angle and not drive that fast till you get it figure out