The Q45's HP ratings are probabily slightly falsified and I think Nissan has some power-sucking transmissions.
I don't know how this topic got started but I will agree with both sides. My dad used to have a GS400 and it was a very nice car. It had a powerful yet smooth as butta' engine. I think Toyota is capable of building a performance engine. If Honda and Toyota were in a 'Build a Performance Engine' contest I think we would see two totally different engines, Honda's being a naturally aspirated four-cylinder and Toyota's being a four or six-cylinder with some kind of artificial aspirated. Both would have their strengths, both their weaknesses.
At this time though, Toyota chooses not to offer a 'performance' engine in the US market. I personally think the MR2 Spyder or whatever it is officially called should have the 180hp as the Celica GT-S and Matrix XRS/Vibe GT.