I was considering Bruiser because they are only an hour from me and I can check I the Jeep during the who process.
Yes the W5A580/NAG1 transmission in the '12+ can handle the V8 power for sure. Its put behind SRT8s, AMGs, and 911s. Its rated at 580NM aka 427 ftlbs TQ. The AMG shift solenoids and TCM programming will up that rating... BUT I have priced the Bruiser conversion LS vs the RPM and Motech with the 6L80 and the pricing is the same.
And I have decided not no go with any of the 3 shops. Bruiser has been pretty bad with communication with me and the others are so far. I have found a shop 45 minutes from me in the other direction that I'm going with. When I'm ready they will do the engine swap and I trust them to decide what swap parts to buy from what company and that things they will make in house (the Jeep & 4x4 shop also owns the engine machine shop next door). I have read everything that I can about everyone's swaps and know that until I have actually done a few swaps without attachment to any kits maker that I won't know what way is best for me. So this is where a trusted shop enters in.