That thing is bad ***. In all honesty i wish had an old 4 door chevy like that.
On another note about the Allison, my friend says automatics are the way to go with a diesel because the turbo doesnt despool between shifts like with a manual. But IMO that isnt really a big issue. As of now, my truck is mostly stock and my turbo is pushing gratuitous amounts of boost as soon as i hit the gas again after changing gears, but idk. Personal preferance i suppose eh?