I know the twang of which you speak. You can try adding half (or more) of your LME late in the boil @ 15 minutes remaining. Just take your kettle off the heat and gently stir your extract in. You can also try to cut down on the amount of extract you are using by doing a mini mash to get more gravity points from grain as opposed to extract.
Besides the extract twang, it could be your water. I've found that I have a hard time cloning a beer because my water does not taste like the water used in the commercial beer I am cloning. Not that my beer is bad. It just comes out different. How many batches have you done? Are you cloning, or brewing your own recipes?