First off, speed limit was started years ago by Steve Sacco, he drew up the rules and Neil Simpson refined the rules occasionally. Steve called it Geriatric Combat and they call it GX (personally I hate that name), it should just be called speed limit combat, 75 mph or below. Our rules call for 73 mph which is 3.5 seconds per lap, however if both contestants are flying the same speed up to 75 they let it go. As far as engines I've been running OS 32 SX for around 8 years, it's a wonderful engine and it's a down right shame that OS discontinued them (of course, you had to modify them from RC to CL); they start and restart excellent and run equally as well on hard tank or bladder, 9/4 for hard tank and 8.75 for bladder, 10% fuel, K&B 1L plug works fine. Lately I've been playing with S/T 34 from China (it is made far better than the Italian version), it weighs the same as the OS 32 and comes ready to run in CL version for $70 from Towers; it is a ringed engine but this is not a problem (in fact, in case of a rebuild it could be a plus). First one I ran, took it out of the box, installed the supplied venturi and nva, open the needle 2.5 turns and that where it has run to this day (a good cheap engine). As far as airplanes, naturally I prefer my Yankee Nipper design, this is a very tough airplane ( drive it straight in the ground, change a prop and go up again), if you break the wing cores simply replace cores. More information on this can be found on the New England website.
By The Way, speed limit combat has replaced AMA Slow, so everything that's flown on .018 lines regardless of engine size and the pull test is 35 pounds.
Jim Carpenter