I think some clarification might be in order, here. My airplane, a Q200, originally had a single-rotor Wankel that weighed, firewall-forward, right at 200 lbs with a Ross PSRU and aluminum end housings, wet, with a wooden prop. The builder wrote extensively about this airplane in Kitplanes during its development and did a nice job on all of it, though not without a learning curve. He put the output, naturally-aspirated, at around 130 HP. He has stated to me that he plans to use another Mazda engine in his next airplane, which will be his seventh build, having been very impressed with the end results on airplane number six. Unfortunately, someone else made an offer on the engine/PSRU separately and he sold it a few hours before I contacted him about the plane. I'd like to duplicate the previous engine in rough numbers, with an aluminum single-rotor and a similar PSRU. Single-rotor 13Bs don't have as good a HP:weight ratio as dual-rotors, but they're still very good, and excellent for aviation. Using aluminum end housings saves a lot of weight, as well, but they're expensive at around $2000 each.