These are the best selling sports cars in America for 2017. The sports car market is a strange one. It goes up and down more than sales of sedans, SUVs, and trucks, with models dropping and gaining by 20 percent or more. That's because while a new family sedan or a new pickup might be a necessity, a sports car rarely is.Sales of sports cars were down sharply last year, down just over 7 percent. But there were some highlights in the list of the top 10 best selling sports cars of 2017.10. Infiniti Q60: 10,751 units soldThe extensively revised Infiniti Q60 went on sale in late 2016. The new model had sharp looks, and a range of engines from a 211-horsepower turbo four to the massive 405-horsepower 3.0L twin-turbo V6 in the all-wheel drive Q60 Red Sport.The good looks, big power, and loads of active safety and tech features catapulted sales. They were up 170 percent from 3,970 the year before.9. Mazda MX-5 Miata: 11,294Next up on the list is one of the most iconic sports cars of all time. Despite nearly 30 years and four generations, the new Mazda Miata MX-5 is nearly as small and as light as the original. With handling that might be even sharper.The current car's 2.0-liter four and 155 horsepower might not sound like much, but in a car that weighs just 2,300 lbs, it's plenty. And if you don't want an open top, the RF's folding hardtop keeps the weather out and looks even cooler than the convertible. Sales were up 19 percent from 9,465 in 2016.8. BMW 2-Series: 11,737From the 248-horsepower 2.0L turbo four of the 230i to the 365-horsepower twin-turbo inline six in the M2, the BMW 2-series offers a wide range of coupes and convertibles.It has sharp BMW handling, compact size for nimbleness and agility, and a driver-focused cockpit. Step up to the M2 and experience performance that was exclusive to supercars just a few years ago. But the BMW 2-Series saw a sharp drop in sales this year, down 3,782 units.7. Audi A5: 21,301The Audi A5 and S5 might cover the widest range of offerings on this list. There are coupes, convertibles and the the four-door-coupe-hatchback Sportback. If that's not enough, they are offered as the sporty A5 and the full-on sports car S5.The A5 offers 252 horsepower and 273 lb-ft from a turbocharged four-cylinder, along with standard quattro all-wheel drive. The S5 has a 354-horsepower turbo V6 with an optional sport rear differential. With the Sportback joining the lineup for 2017, it's no wonder sales spiked from 8,354 in 2016.6. Chevrolet Corvette: 25,079The base Corvette Stingray starts with a 6.2-liter V8 that makes 455 horsepower and 460 lb-ft of torque. If that's not enough, the Z06 adds a supercharger to the engine that boosts power to 650 horsepower and 650 lb-ft.A seven-speed manual is standard, with an eight-speed automatic optional. Add the Magnetic Ride Control suspension and the Corvette is one of the biggest performance bargains around. But sales were down from 29,995 in 2016.5. Volkswagen Golf GTI/R: 25,192The VW Golf GTI is one of the classic hot hatches. It was one of the first of its kind way back in the 1970s, and the new model continues the tradition. You get 220 horsepower from a 2.0-liter turbo-four, a six-speed manual, or a six-speed automatic. Plaid seats and a golf-ball shifter are still standard.The GTI is one of the most fun cars in its class to drive on real roads. If you want more power and grip, the Golf R boosts power to 292 horsepower, adds all-wheel drive, and an even stiffer suspension. GTI and R sales were down 6 percent from 28,427.4. Subaru Impreza WRX and STI 31,358 soldSubaru's hot Impreza sports cars are the rally icons you remember from the late 1990s - or maybe from "Gran Turismo" - updated for today.The WRX offers up 268 horsepower, while the STI with a 2.5-liter four makes 305 horsepower. But the Impreza twins are still on an old platform while the lowly base Impreza has been on a new platform for over a year.The only automatic is a CVT and it's only on the WRX. Both of those could explain why sales were down just under 6 percent from 33,279 in 2016.3. Dodge Challenger: 64,537Dodge hasn't made many updates to the basic Challenger in a long time. But that hasn't stopped the company from making more and more performance and special trim models. The most recent was the 800-plus-horsepower Dodge Demon that's designed for the drag strip.The basic Challenger uses a 3.6-liter V6 that makes 305 horsepower. Then there are four V8 options: 5.7-liter and 375 horsepower, 6.4-liter and 485 horsepower, a supercharged 6.4 that makes 707 horsepower, and the Demon. Sales were steady, up slightly from 64,433 in 2016.2. Chevrolet Camaro: 67,940The Camaro is one of the classic pony cars, and it continues to sell well - it is second on the list of best selling sports cars. The Camaro offers V6 and V8 power, but there is also a 2.0-liter four that can move, but makes things a little easier at the pump.The ZL1 adds a supercharger to the 6.2-liter V6 and makes 650 horsepower in a track-ready monster of a car. Sales of the Camaro fell 6.6 percent last year compared to 2016.1. Ford Mustang: 81,866The Ford Mustang was the original pony car, and the sports car that lives on today still keeps the affordable performance values that started the brand.The Mustang, the best selling sports car in 2017, accounts for nearly 20 percent of sports car sales alone, even with the huge drop from 105,932 units sold in 2016. The Mustang offers four-cylinder and V6 performance, as well as more and more powerful V8s on option as you walk up the options list.