A Few Questions About A Body Drop On A Hardbody

I'm helping a friend body drop his 89 Hardbody and we have a few questions. We want to lay doors, so how much of a body drop is needed? We'll probably roll the factory wheels for a while, but might step it up, not for sure. Somewhere around 5 inches should lay doors on stock wheels, right? We've also thought about just laying rockers so how much would be needed there? Also, can the torsion bars on the front be completly removed if we're going to bag and maybe dro it? Or should we leave some parts, or what. Any other things we should be aware of such as the carrier bearing?