I second Wolff Springs. This morning I received a mainspring for my Model 15-4 and recoil springs for my 5946 and 4046. I've never seen bad feedback on this forum or any other as relates to their products. I ran their springs on my duty Sig P-229 40 S & W. It ran like a sewing machine.
You may wish to inquire about their LE/MIL discount.