Can a surefire G2 be mounted on a m4gery without any problems?  Will the bulbs hold up to the shock of the recoil?  Also can you get a pressure activated switch to run to your vertical foregrip for the G2?

Yes and No.   A lot of people have mounted a G2 with zero problems, myself included but there a others who have had a problem with blbs blowing.  I would say more people have had good luck than bad with the G2 but ultimately it was not made as a weapon mounted light.  The best way to minimize a bulb failure with a G2 is to buy a shock isolated bezel but that still does not garuntee that you won't have a problem.  

I have had my G2 with a M2 shock iso bezel and a tape switch for a while with a lot of rounds through it without a single problem.  The G2 has served me well but as soon as I have the money I am going to switch to the MU light system.

Talk to Calvin from Brightflashlights he can give you all the info you want and more.  He also has everything you could possibly need or want.  He sells a Surefire tape switch and also a much cheaper but good quality after market one.

I’ve had my G2 with shock isolated bezel mounted on my M4 for quite some time now, no problems as of yet.

my G2 has been on my AR for 500 plus rounds. have had no problems with it to this point