Version 0.4 is up, with a better instrument panel arrangement, including new RPM and MAP instruments. The engine and prop files have been tinkered with a lot, trying to get higher speeds. It's been an interesting process, and the main lesson learned is that you have to slow the props down to keep the helical tip Mach from eating up all your power. I've slowed them to 1500 rpm, and I'm still getting a helical tip Mach of .913. I'll try slowing the props down a bit more. Here's a screenshot showing relevant parameters during a high speed run.
Word: don't pull more than about 30 inches of MAP for takeoff or you'll overspeed the gear for sure.