so what is your question, are you trying to decided which car is best. well the Audi Q5 and Acura MDX are both cross-over luxury and the Lexus IS is a midsized Sedan. so if i had to choose, I will go with the Acura is big, spaces and roomier and have 30HP more than the Q5 and however, the Q5 is very rare to find and you don't see it often which will be quite unique when you drive it by people but it cost a lot to maintain, the Acura is cheaper to maintain but less fuel efficiency than the Q5. And the IS is a different type of car, it has two engine, IS250 which comes with 204HP V6 and very fuel efficiency and IS350 305HP V6. so if you want a small car, go with the IS and if you want the bigger suv than go with the MDX. good luck. and yeah test drive them and see which one you like.