Just a guess but I'd say maybe you should look into some DiMarzio Super Distortions.
yes I eard good comments on them specially to get a full-on metal sound.
I ordered a set (bridge/neck) of GFS VEH, Vintage 59 with a hotter output but they were B.O...so I'll go with the Power Rails!
They're suppose to be really hot for a good metal rhythm attack but they still have the warmth of more vintage P.U...I don't want to sound like a new-metal too much.
I will supposedly feel my palm muting and my pick attack louder and with lots of bottom with them...
I'll see how it goes...should get them next week!
The next option could be DiMarzio D-Sonic, they are good for drop tune...but twice the price!