Below are the actual typical weights of the misc. components required to run the BME-55 or anything in this size range.

2.0 ozs. Aluminum CNC radial engine mount
3.7 ozs. C&H Auto Ignition unit
1.6 ozs. sparkplug
5.2 ozs. NiMH 4-cell with switch
7-9.5 ozs. Pitts style exhaust cannister.

19.5 to 22.0 ozs. or 1lb.- 3-1/2 ozs to 1lb.-6 ozs. plus the bare engine weight.

Extreme 55's percieved weight of 2lbs-2ozs + 20ozs = 54ozs.

I have owned several BME engines they all weighed pretty close to the advertised weight stripped, less sparkplug, ignition, prop-bolt(s) and of course engine mount.

So the NEW Extreme should weigh in about 3lbs-6ozs. all up. Average lighter weight as compared to other engines in this size that are considered lighter engines will be around 10ozs.

Past BME engines have never been known for their lack of vibration, properly tuned or not! If this little guy makes the purported power at the suggested weight without beating itself/model up it will be another winner from BME...