That makes some sense, right? The Mustang has to be cheaper than those competitors, right? Not really. Both the EcoBoost and V8-powered Mustang have higher starting prices than the equivalent TT. The 2.3-liter, EcoBoost-powered Mustang starts at 38,000 euros (around $43,300 at today's rates), while the front-drive Audi TT starts at 35,950 euros (about $41,000). The V8-powered Mustang GT, meanwhile, starts at 43,000 euros (about $49,000), which is just 2,550 euros more than the Quattro-equipped TT. When 310 horsepower or 435 hp can be had for just a couple thousand more than 220 hp, it's easy to understand the Mustang's success.
The 911, of course, is a lot more expensive than the Mustang. You can buy two Mustang GTs for the price of a single Carrera. But Ford also managed to beat out the Porsche's smaller siblings, the Boxster and Cayman twins, which sold a combined 642 vehicles. Again, the pony car is significantly cheaper, but that doesn't do much to lessen the impact of the Mustang's victory.
If you're in Germany and are concerned about this American invasion, you shouldn't be (yet). The TT is Germany's best-selling sports car from January through March, with 2,299 to the Ford's 1,823. Porsche is breathing down the pony car's neck, too, with 1,811 units in 2016. It'll be interesting to see if Ford's successful March carries on into the rest of 2016.