Most reputable tuners offer transmission safe tuning. The 5 speed Allisons will take about 100hp over stock and the 6 speeds can deal with about 120 or 130hp. That's also why I listed out what tunes mine has...there a lot of stuff you can do with them. The Spade isn't their single tune...it's an EFI AutoCal and it comes setup to use a DSP5 switch according to the information on their website. You purchase the tunes themselves for 400 bucks and the AutoCal is an additional 309 bucks and 40 for the switch. That's 799 bucks all together. You should be able to load the tunes individually, but you'd still have to buy the AutoCal and tunes.
That's also why I'd suggest finding someone local or just taking a drive to have someone load the tunes for you. Then you don't have to buy the extra stuff. They just load you up whatever tune/tunes you want and you go on about your business. If you DO buy tunes online or something like that, you do have to have an AutoCal or EFI Live V2 to load the tunes in to the truck via the OBDII port, so just keep that in mind.
I'm not pimping Diesel Addiction's stuff (although I do like my tuning), but here's what they offer, just for reference.
Single tune - $350
2 position switch installed with 2 tunes - $475
5 position switch installed with 5 tunes - $575
Again, this is all if you/he wanted to go with EFI Live style tuning. There are a bunch of different kinds of tuners out there. The H&S like mentioned above and Edge CTS are nice because the have a display panel and you can also use them to store, load, and switch between different tunes.