Replacing spark plugs on my X5

[igorbmwx6]

Has anyone replaced spark plugs on a E70 X5 3.0si? I purchased a set of 6 "BOSCH - 0242236510 / FR7NPP332" plugs. Brand new. I have several questions:

1.) Are these the best plugs to use?
2.) I now have over 50k on my car, is it a good time to replace?
3.) Do I need to adjust gap size before installing or factory setting is ok?
4.) If factory setting is not ok for the gap, what should it be set to?
5.) What is the torque for re-installing these?

Thank you in advance for all your comments/suggestions ...