I upgraded/customized my TM G36C into a G36KV:
http://img440.imageshack.us/img440/9...kv10241zk4.jpg
I got the G&P version of the SRC stock you mention a G&P "K" front set and a Star flat top rail.
You can put up to a 12v large battery in it. I use a 9.6v 4/5 sub c pack which allows the stock to be in the second shortest position.
I am using a Madbull 6.03 x 363mm barrel with it.
I'd get a TM hop up unit, they are the best.
To upgrade your muzzle velocity to where you want it, you are basically going to have to rebuild the internals/electrics of that AEG.
Good luck.