The trigger and fire control group kind of IS the LPK. Buffer tube doesn't matter, stock matters. Geisssele makes the best (as pennywise67 mentioned); however, considering that for the cost of a Geissele is about 4 times that of a standard trigger group i have a hard time justifying one. A standard trigger with a polish job feels pretty good and I have lots of spare parts. The parts on the rifle that make the greatest difference to accuracy are all in your upper receiver. With limited resources, I would spend the extra money on a nice SS barrel and good optic. Otherwise, if money is no object just buy the best of everything and make it a Gucci gun.