The most common crash on a paramotor is when the pilot lifts his or her legs too early on take-off, resulting with a bum landing with the full revving propeller digging trenches. In this instance a clutch cannot help. There is an argument for not having a plastic tank just over the hot engine and exhaust, for obvious reasons. The ability to close the venting of the petrol tank while transporting it in the car is essential. A float carburettor has the same problem of petrol drip and smell, unlike the fully sealed diaphragm carburettor.
Fuel economy is very important.
Air filters are commonly used, sometimes with air intake mufflers which also reduce noise. Remember the cage will reduce your paraglider's maximum glide ratio. Obviously temperature, pressure, altitude, humidity and optimistic manufacturers' figures affect this theoretical equation. Some manufacturers will experiment with new ideas or components directly into their production lines, without a test program, waiting for the phone to ring to see which idea works and which doesn't. Most paragliders are suitable for paramotoring, with a few notable exceptions.