Hi Phil,
From you post it is not easy to know what you are really looking for.
A luxury coupe: Lexus have some great, well-built and extremely comfortable cars.
A sports car: Lexus do not make sports cars.
Have had sports cars. They are noisy and not comfortable; no rubber bushings: metal on metal. My wife disliked them.
Have passed the time when wanted to come fast from one place to another, now comfort and reliability is what we need.
Have had BMW cars. Never loved one of them.
Have had MB cars. The 300SEL 6.3 was comfortable, air suspension fabulous at the time, but a stupidly large car that it is impossible to find a parking place for. Smart Roadster Coupé with paddle shift was the closest to an MB factory built I liked. My mother loved the 190SL though and called it Andy Capp.
Lexus cars are not bad in any way except for infotainment and navigation systems in them.
The coming Genesis looks interesting and with the built quality of Hyundai they could be the next reliability top.