Complex sentence: The Menasco engines were interesting in that they came in both normally aspirated and supercharged forms, with the supercharged models exhibiting superior performance at higher altitudes, with a relatively small increase in dimensions and weight.
Split into simpler sentences: The Menasco engines were interesting in that they came in both supercharged and non-supercharged models. The supercharged models had superior performance at higher altitudes with a relatively small increase in dimensions and weight.