The kits are not worth the money on the 5speed Allison's anyway. The 6speeds are a different story. EFILive is the way to go for sure on tuning and he could get a switch and turn it up or down (down while on stock trans).

 

So his best best is a efi live tune and built tranny I'm assuming. Not worth the time and money for a shift kit

 

Correct. where does he live? I can send you some contact info if your near any of the builders that I know of.