Question: The BMW N63 engine was launched in a mid-sized luxury what?

Context paragraphs:
BMW New Six: The BMW New Six (E3) is a line of full-size luxury sedans produced by the German automaker BMW from 1968 to 1977.  All models used the then-new M30 straight-6 engine.  It marked BMW's return to the full-size luxury sedan market after a hiatus of 5 years, was introduced as a response to growing market segment dominated by Mercedes-Benz.  It was important in establishing BMW's reputation as a maker of sporting, luxury sedans.

Toyota Brevis: The Toyota Brevis is a former mid-sized luxury sedan introduced in May 2001, that was sold only in Japan.

BMW 501: The BMW 501 was a luxury car manufactured by BMW from 1952 to 1958.  Introduced at the first Frankfurt Motor Show in 1951, the 501 was the first motor car to be manufactured and sold by BMW after the Second World War.  The 501 and its derivatives, including the V8 powered BMW 502, were nicknamed “Baroque Angels” by the German public.  The BMW 502 was the first postwar German car to be manufactured with a V8 engine.

BMW B57: The BMW B57 engine is a straight-six cylinder turbodiesel engine produced by the automobile manufacturer BMW.  Together with the B37 (three-cylinder diesel engine), the B47 (inline-4 cylinder diesel engine), and the three inline-4 and inline-6 petrol engines (B38 (three-cylinder), B48 (four-cylinder) and B58 (six-cylinder)), the B57 is one of the latest (as of 2017) modular engines from BMW.  The modular motors are used in BMW models as well as in MINI models.  The B57 replaced the N57 diesel engine family in the new 5-series and 7-series.  This new engine is available in configurations with up to 4 turbochargers that operate in a double-series layout.  Output is up to 400 horsepower and 569 lb-ft of torque.

BMW N63: The BMW N63 is a twin-turbo DOHC V8 engine which has been in production since 2008 to present.  It is the world's first production car engine to use a "hot-vee" layout, with the turbochargers located inside the "V" of the engine.  It is also BMW's first V8 engine to use direct injection.  The N63 was launched in the 2008 BMW X6 xDrive50i.

BMW 303: The BMW 303 was a small family saloon produced by BMW in 1933 and 1934.  It was the first BMW motor car with a six-cylinder engine and the first BMW motor car with the "kidney grille" associated with the brand.  The platform developed for the 303 was used for several other BMW cars, including the BMW 309, a four-cylinder version of the 303, the BMW 315, a 1.5-litre version of the 303 which replaced it in 1934 and was built until 1937, the BMW 319, a 1.9-litre version of the 303 produced alongside the 315 from 1935 to 1937, and the BMW 329, a development of the 319 with styling based on the newer, larger BMW 326, that briefly replaced the 319 in 1937.

BMW X5 (E53): The BMW E53 is the first-generation BMW X5 mid-sized luxury crossover SUV.  It was produced from 1999-2006 and was replaced by the BMW E70.  The E53 was developed at a time when BMW still owned Land Rover and as such shares many components and designs with both the Land Rover Range Rover L322 model (specifically the Hill Descent System and Off Road Engine Management system) and the BMW E39 5 Series (specifically engines and electronic systems).  The entire in-car entertainment system (Radio Function, Navigation System, Television and Telecommunications systems) are shared with other BMWs and L322.

Cadillac STS: The Cadillac STS is a mid-sized luxury four-door notchback sedan manufactured and sold by Cadillac from 2004–2013.

BMW X6: The BMW X6 is a mid-size luxury crossover by German automaker BMW.

BMW M67: The BMW M67 is a diesel automobile engine, used in the BMW 7 Series.  It was first introduced in 1998, and used until 2009.  The engine is a common rail turbodiesel V8 design, using double overhead camshafts and 32 valves.  It was the first luxury car application of a bi-turbo diesel intercooled V8 engine.  The 3.9-litre iteration won the "3-4 l" category of the International Engine of the Year award in 1999 and again in 2000.  It was replaced by the 6-cylinder N57 engine.

Supporting paragraphs: BMW N63 BMW X6
Answer: crossover