The "almost as good substitutes" are the SAME engine with different names on the crankcase, so don't worry about that. Magnum 15's are easy to get. Just call Tower or Hobby People. Granted they cost more than an ASP from Hobbypartz, but for $70 they are still about the cheapest 15 on the market. I'm sure Bob can make a venturi, or for $10 he may decide it's just as easy to buy one from me. Done. problem solved.