Build a wooden crate or use a cardboard box for Amplifier.

I would crate the cardboard. You need a crumple zone to absorb the impacts. If you build a solid crate and the amps are fixed in a solid position they will still take all the hits and vibration. Just like a car bumper and a bike helmet they absorb the impacts through a crumple or break away material. Good luck and enjoy the music!

Since I ship heavy equipment weekly, wood crate and mount it to a pallet.  Can't be turned upside down or dropped like a box can.

Happy Listening.

Anything over 125 pounds you will want to go to wooden crate. Yet, Resolution Audio has been using wooden crates for their new Cantata and M100 amps for years. CJ switched to wooden crates for the ART27A amp. We at Penaudio just shifted to wooden crates for the new monitors. Look for local box company. They can make crates and supply foam. You will want 3" of foam to keep the amps safe. If they are going in a moving van, then tell them where and how you want them stacked.

lots of options here with most of them you doing the work. talk to the movers and give them your expectations / specs and see what they can do.....palletized , double wall construction with added padding for insurance should be no problem.....issue is the cost  

and the insurance....if you pack vs they pack what is the impact on any insurance issues ....if any