Ruling on taking a Mus-haf from the mosque, elongating the back excessively during prostration, and fidgeting during prayer
Question

                What is the ruling on taking a Mus-haf home from the mosque, especially if one is hesitant about doing so? 

What is the ruling on elongating the back excessively during prostration?

What is the ruling on raising one’s voice when reading the Qur’aan before the prayer?

What is the ruling on playing with one's beard or clothes needlessly during the prayer?
Praise be to Allah.
    With regard to taking the Mus-haf from the mosque, this is 
    not permitted, because the Mus-hafs of the mosque should stay in the mosque 
    and not be taken away. 

    With regard to elongating the back excessively during the 
    prostration, this is not appropriate. Rather the back should be moderate 
    when prostrating, not stretched out too much and not bent too much.  The 
    back should be moderate  with the arms lifted up off the ground and the 
    elbows away from the sides, and the stomach lifted up off the thighs, i.e., 
    one should follow a middle way, not stretching it or bending it too much.

     With regard to raising the voice when reciting Qur’aan 
    before the prayer, you should not raise your voice if there is anyone else 
    present, rather you should read quietly to yourself, so as not to disturb 
    other people or distract those who are praying or reading Qur’aan. But he 
    may raise his voice a little.

     With regard to playing with one’s beard or clothes while 
    praying, this is makrooh. The Sunnah is to remain still. Allaah says:

    “Successful indeed are the 
    believers.

    Those who offer their Salaah (prayers) with all solemnity 
    and full submissiveness”

    [al-Mu’minoon 23:1-2]

     So you have to be solemn in your prayer and not play with 
    your beard or clothes. A slight movement if necessary is forgiven, but a lot 
    of movement is not permitted unless absolutely necessary.