If budget is not a limitation, then the best 5-6 seater will have to be a three-row luxury MPV, as luxury sedans are fundamentally designed for four people, and three-row luxury SUVs have compromised third row comfort.
For 5-6 people, the Toyota Velfire is the most comfortable, as even the third row has good space all around and comfy seats that are almost on par with the second row. You get lots of features and storage space, which makes it like a lounge on wheels. But at Rs. 1.58 to 1.7 crore (on-road Mumbai), it is very expensive. 
