Building heavy is a lot harder to do than just adding heavy equipment. At 17 pounds, I would guess you used a large gasser with a slimline Pitts style muffler, aluminum spinner, CF prop. and nicads or nimh's instead of li-ions or lipos, and maybe even added a pilot and cockpit.
This plane can be built down to under 13 pounds if the cards are played right and you don't mind nitro...