A million factors play a part in value increases.
Things like popularity, rarity, historical importance, design trend, aesthetics, and a growing market value (investments) all play their part to influence values for good or ill.
Recently, BMW's M series has been seeing some good increase in sales prices.
BMW first introduced the M series in the 1970's, so to narrow down some of the factors, we'll focus on the cars built from 1978 to 1991.
Like many automotive brands, successful racing history has contributed to the success of the BMW Motorsports brand.
So naturally, we'll start with the BMW super car, the M1.
Giorgetto Giugiaro designed the car with styling inspiration from Paul Bracq's 1972 Turbo concept, and a a twin-cam, 3.5L inline-6 powered the M1, producing about 280hp.
BMW built the M1 to be a sports car for the street, but, being the BMW Motorsports division, the company created about 20 cars for a one-make auto racing series, called Procar.
Formula One drivers raced these cars at select Grand Prix races during the 1979-80 F1 seasons.
BMW produced only 453 M1 total (street and race versions).
The rarity, the unique design, and racing history have made the M1 incredibly desirable to collectors, such that values have more than doubled in about the last five years.
Today, an excellent example will cost about $600,000.
But, the M1 wasn't the only M series car BMW took to the track.
Enter the M3, possibly the most well know BMW race car. BMW produced the BMW E30 M3 from 1985–1992 and dominated the World Touring Car Championship for several years.
This success, along with the sales success for street cars and affordability made the E30 M3 a very popular choice for many to own and experience. BMW produced about 16,202 E30 M3's. And even though BMW manufactured a relatively large amount, market values have gone through the roof, with some of the special edition cars selling over $140K.
The BMW M5 E28 was BMW's other great motorsports offering to the North American market. The 5 series cars were the everyday businessman or family car, but with the introduction of the M option, the cars became the "sleeper" high performance car.
BMW originally offered the M to Europeans as the M535i, starting in 1985 and ending in 1988, and offered the M5 for the North American market from mid-1987 as a 1988 model (a one year only model).
Originally, BMW planned to offer only 500 units, but with a high demand, BMW increased the number to 1,340.
Great handling, performance, luxury, and room for five have made the M5 one of the best all around BMWs.
The motor was a variant of the original M1 twin-cam 3.5L inline-6, but detuned and modified to meet U.S. emission laws. Although the M5 did not see the same track use as the M3, it gained it's true reputation from the Autobahn and just like the high speeds of the Autobahn, the M5 market values have been cruising higher and higher.
In some cases, values have increased by 5 times as much in the past 3 years.
Like the M5, BMW first offered the car to Europe as the M635CSi. BMW then offered the M6 E24 from 1987 to '89, with 1,767 vehicles coming to North America. 1,632 went to the U.S. (135 went to Canada). The engine in the M6 (as well as the M5) was a variation of the original M1 3.5 inline-6.
The M6 gained it's popularity for being the prettiest and most stylish luxury sports coupe a businessman could drive to cruise at Autobahn speeds. The price of the M6 in 1987 was $58,000 (base), which was more than the M3 ($35,000) and M5 ($47,00). In the past couple of years, the M6 has increased in value by 60%
A few features also make these early M series cars unique.
All cars came with 5-speed manual transmissions. All cars had a twin-cam motor, which was unique to BMW during this era. BMW's Paul Bracq designed the entire line, and possibly the most important aspect is the introduction of the street version M Motorsport department.
Some photos of our M6.