Thats why the BME 58 is the hands down winner. More or equal power than a 50cc engine on a pipe with the benefits of a super lightweight set up. Yet put a pipe on the BME and it weighs the same as others with stock exhaust and now the power can really be noticed. Each way the BME wins.
You can't say the BME 58 doesn't belong in the 50cc class since it is designed to be for planes in that class.
If you want to exclude the BME 58 then change the poll to read.... Whats the best of the over weight under powered 50cc class engines.