I have run a MACs tuned pipe on an MVVS 2.5. I ran it with an 8x4 prop, but this was when I was a beginner in RC, 12 or more years ago. I do remember it ran fine and seemed to come up on pipe as would be expected. This engine however now has a blown little end in the rod, but I think that is related to running it once every few years and not cleaning the lubrications holes in the rod prior to doing so.

I remember an old RCM article(I should still have it somewhere) about a ducted fan running a Rossi .80(?) on a pipe and the author said it was fine as diesel and made more power than the glow setup. They took an existing airplane and dieselized it.