Best Penetrant to Remove Differential U-Bolts?

I understand what you are saying but MY car is not a factory 318 car with 8" wheels.

It works for me and i dont have to worry about trying to use 1/4" U bolts to hold my axle.

I personally have had a drive shaft inside the car twice. The first time my buddy was lucky not to loose hos feet and the second time it let go when the axle twisted, pinion gear sheared off and it came in through the back seat. So its something i take seriously.

My drive shaf hoops are inch and a quarter by one twenty wall. I will never have the drive shaft inside my car ever again.

Over kill, yes.
Not worry about a 5 foot long chunk of metal inside the car spinning at a ridiculous speed.

Priceless.