Tom
The engine kit you refer to has all aluminium castings - including the flywheels! It is designed to be glowplug ignited, but could be converted to traditional points type ignition quite easily. Quite an attractive engine in my opinion, but would best be described as 'near scale'. If you are on the 'other side' of the pond, then you will be disappointed to learn that the gears, springs, etc. are all extra, unlike US supplied kits.
There was a build series in Model Engineer by Stan Bray in the 1990s sometime. With the Ali flywheels, he could not get it to run. One modification is to machine off as much of the rim as possible and substitute steel rims for extra weight. This has proved successful although a slow running engine is hard to achieve.
To put it delicately, some folk have not been too pleased with products from the Engineers Emporium or their service, but you take them as you find them. They are still in business so others must be purchasing their wares.
Dave
The Emerald Isle