I don't believe I mentioned Taurus-or any brand-
but I have seen many postings on 50 size engine touting the small props and high rpm.
Thes setups are frankly noisy-
I do judge good aerobatic engines by their raw torque .
I don't spend much time on 3D stuff.
Just not my cup of tea -for the most part.
The .46 powered Diablotins are kinda fun -and dead silent with Ed's CF pipes.
I put one togather for a friend and another friend has one. I have flown em .
I tried to write my comments so as not to pick out particular engines.
Some new guys actually believe a 100 rpm here and there is an exact, repeatable condition.
I did tach one of my ZDZ40's (sold it) with a Mejzlic 24x10 at 5900 rpm-since you asked tho.
I was surprised -but it did it repeatably.
more typical is a 20x10 Menz's -or Zinger Pro-in the mid 7000 range.
The motor mount thing ?
This is quite simple -at least none of the guys I know have considered it a task. I have added no parts on most planes -just shifted mounting plate forward . The little drilled 1/2 " dowels are only a few grams -when I use that approach.
Quiet exhausts are something I started with -and I really would not be comfortable with a loud model.
I know some guys love the noise - I don't.
I would also get a ration of crap from my friends.
My FAI project is being done to see if I can make a quiet, very strong performing gasoline model suitable for FAI-and the little ZDZ Rear Exhaust loos like the best candidate.
It will fit into a very small space -with no protruding exhaust or carb.
If you have a better suggestion -please let me know.