Devl,
You may want to think again about the G2 on your rifle. It is basically a 6p in polymer vs. aluminum. If you check some of the other posts, even with a shock mounted bezel, the batteries will batter the contacts and eventually your light will fail. It isn't designed as a weapon mounted light.
Here is my idea. Haven't bought the components yet but it seems to be the best I can come up with for the money.
I bought one half of a fobus handguard with the built in rail. It goes on the bottom and uses a standard CAR handguard on top. I know, I wish it was M4 sized, but it isn't.
I'm planning on getting one of the TACM-III lights with the tape switch and mounting it to the bottom with the fobus light mount. It uses the springloaded catch like an M3 so it is easily detachable.
I still haven't decided if I want to try one of the vertical foregrips. I've not heard any complaints about them, but I guess I'm a little old fashioned. So, I'm either going to trim the little slide off handguard section so I can cover the rail behind the light, or I'll get a vertical foregrip and use that.
This is several hundred dollars less than the top of the line surefire's and at least $100 less than the lowest surefire combo.