I have a 2012 QX56 with bent valves. I am thinking about swapping the engine with another one but I want to size the job up first. I am looking for someone who has done this in the past.

Questions:
1.) Do I have to drop the tranny or can I leave it in?
2.) Unbolt the exhaust manifolds in place or pull them out with the engine?
3.) Anything that I will need to replace or factor in the cost as part of the process? (i.e. sensors, seals, electronics reprogramming, etc.)
4.) Best to use the Infiniti sold engine slingers?
5.) What else should I be asking?