The Boeing vs. Airbus debate seems never-ending. However, I've never encountered a powerplant debate and am really not too familiar with powerplants, except that the major suppliers of powerplants are Pratt and Whitney, Rolls-Royce, and GE, both serving Airbus and Boeing.

Here are my questions:
* Why do the aircraft manufacturers even give powerplant options? Doesn't that increase complexity with regards to integration with the aircraft systems? Looking at the A333 and B777, there are 3 options, with maximum thrust differences being really negligible. Why go with one over the other?
* With regards to powerplants, does the aircraft operator directly work with the powerplant manufacturer in terms of "warranties" and "recalls?" Or is the aircraft manufacturer the intermediary?
* When pilots are certified to fly a certain aircraft type, are they also "stuck" to a specific powerplant? What if the aircraft operator decides to buy more of the same aircraft type but with different a powerplant manufacturer? Is there additional training required for the pilots?

Moderator, feel free to move to Airliners.net.