Super, sport, and race cars frequently have a mid-engined layout, as these vehicles'
handling characteristics are more important than other requirements, such as usable space. In dedicated sports cars, a
weight distribution of about 50% front and rear is frequently pursued, to optimise the vehicle's driving dynamics – a target that is typically only achievable by placing the engine somewhere between the front and rear axles. Usually, the term "mid-engine" has been primarily applied to cars having the engine located between the driver and the
rear drive axles. This layout is referred to as
rear mid-engine, rear-wheel drive, (or RMR) layout. The mechanical layout and packaging of an RMR car are substantially different from that of a front-engine or rear-engine car. When the engine is in front of the driver, but fully
behind the front axle line, the layout is sometimes called a front mid-engine, rear-wheel-drive, or
FMR layout instead of the less-specific term front-engine; and can be considered a subset of the latter. In-vehicle layout, FMR is substantially the same as FR, but handling differs as a result of the difference in weight distribution. Some vehicles could be classified as FR or FMR depending on the factory-installed engine (I4 vs I6). Historically most classical FR cars such as the Ford Models T and A would qualify as an FMR engine car. Additionally, the distinction between FR and FMR is a fluid one, depending on the degree of engine protrusion in front of the front axle line, as manufacturers mount engines as far back in the chassis as possible. Not all manufacturers use the Front-Mid designation. ==Examples==