There are many reasons that keeps me from buying a rear or front mounted engine kit. I like the Robin Subaru kit but won't buy it because it's a rear mount. 1. The Center of gravity is higher for a rear or front mount engine. Thus the bike is not as stable as a bike with an in-frame engine that sits closer to the ground. 2. The weight of the engine for a rear or front mount engine is not distributed evenly on the tires thus effecting steering, maneuverability, and wear on the tires. As compared to an in-frame, that has equal weight distributed over the tires and the tires will wear more evenly and much better steering ability. 3. If you desire to add a basket or saddle bags to a front or rear mount engine there comes some more problems. Besides adding more weight (see 2. above), you increase the height of the CG (see 1. above) since the rack sits over the engine and makes instability that much worse. Furthermore, saddle bags will cover the engine and block the necessary air flow from contacting the engine, thus causing the engine to run hotter than normal and reduce engine life. This airflow to engine is blocked more so on a rear mounted engine since your body blocks the air stream. All of these problems don't present themselves with an in-frame engine. 4. It's a lot easier to drain the oil out of an in-frame engine that sits close to the ground, than a high sitting rear or front mounted engine. Unless you like having to stand and hold the container, on a rear or front mounted engine, while the oil drains. 5. I personally don't find a rear or front mounted engine appealing to look at. In my opinion it just doesn't look good. Each to his own. I like the way an in-frame mounted engine gives more of a motorcycle presentation. I'm looking for an in-frame kit with an American or Japanese engine, around 35cc more or less, that has a max 1.5 HP according to Louisiana law, to be classed as a motorbike. Any comments or suggestions will certainly be appreciated.