Lets look at the facts. The variable valve timing and cam inductions, as well as other known ways of making a 3.0 liter perform like 4.0 liter, all come from one source-racing! Honda, Toyota, Audi, Even Ford through Cosworth have participated in racing serieses that REQUIRED ,because of displacement limits, tricks and ways of tuning engines without increasing displacement. That'* why Honda has a 4-cylinder that makes the same amount of power as GM'* brand-new 3.8L "high feature" engine.
That said, do bear in mind that the advantage of GM engines versus import powertrains is that there is more torque when you need it. Chances are that the 225 horsepower in the Acura isn't any good until you get on the tach. The GXP has its 300 pd/ft at a nice, low tach level. Just say that about an S2000