Does the DriveLine Undercarriage protection from GM just bolt on with no other modifications required????
GM Part # 12498474

Yes.

i had to use a sledge hammer for some moderate adjustment

Thanks...

I have a sledge hammer so that shouldn't be a problem

cool chas i had to start with center bolts and beat the trailing end of rear protection up just a little . i had scraped the cross members up pretty good so had to adjust milk crates help in holding it up close while doing the install . its pretty easy to do even if you have to beat it have fun

Milk Crates... Thanks... Looks like I'll be heading to the grocery store after work tomorrow...

I didn't have any problems installing mine. Bolted right on, no sledgehammer.

They are pretty light too. I was able to just hold them up to the frame while I put the bolts in. Shouldn't take more than 30-45 mins to install. Much easier than the rails.

Same here. No sledgehammer needed on mine. It was a little bit akward do by myself though. A milk crate would have been perfect. I just put mine on my chest and slide underneath.

Normally you just use zip ties for the stock stuff.

We added mine in the parking lot of the hotel when we went to Tellico since I had it shipped there. I can't really tell you if it was easy or not because the guys just climbed under there and started installing, I just handed them tools

Didn't hear any hammering though

Entrestingly enough, not that I'm rich, but lazy didn't have the help/tools needed so had the dealership bolt all my protection on. The cross frame rail that they bolt to didn't have the holes drilled properly, I told them they could probably take a drill and tap the holes but they said it was a defective piece and needed replacing. So it took a couple extra days.