A lot of people complain about Lexus IS not having much rear seat space when compared to BMW 3 series, but what they fail to mention is that BMW 3 series feels less spacious in the front. Me, at 6'-4", I feel really cramped inside the 3 series. Not to say that IS is spacious, but at least I can position myself comfortably enough. Given that both 3 series and the IS are driver's cars, I believe the front space is what counts most. That being said, out of all small sports sedans, IS, 3, TSX, G35, the G35 is the most spacious. I was even comfortable in the rear seat behind my wife driving.