Locally, we have two, models--weighing 11.5 lbs--1280 squares.
each model has a ZDZ40 rear exhaust on a tuned pipe - Lots of power - a little shake at idle but we have both been flying these models a lot --
If all singles were too shaky to use - these models would be junk by now
These models are built with only the strength necessary to stand extreme flight loads -no firewalls - no beefed up parts -anywhere.
rTwins are great too but the singles are also very smooth.