decide if it is possible to cut the foot peg mounts off the frame and re-weld them to the frame in a lower position. Things to consider are shifter and brake pedal locations. I did it to an older KX100 and made a flat steel 1/4" plate that I welded to the frame that dropped down and then I welded the stock foot peg bracket to it. I only lowered them about 1" cuz that is what would work with the brake pedal.
I used a Sawzall type saw to slowly cut the mounts off the frame.