No differences between trim levels....
But through refinement and tweaking, Honda did briefly quote 255hp on the '05 models and then went back to 244 hp for the last couple of years.
The peak hp is somewhere around 5500 rpms, where I only briefly find myself driving at for short bursts. Usually when I feel the urge to hear and feel that sweet, sweet Vtec howl!!
So, the difference from the 03/04's (242hp) to the 05 (255hp) is about 5%, and that is only at wide open throttle at max rpms. I'm not an engineer, but I believe the torque curve between both figures would be incredibly close to each other if graphed on paper. My opinion is that my seat of the pants meter would not notice the difference, but I haven't driven an 05.
BTW- I pull a +/- 3000lb boat and the Pilot does just fine, not great, but fine..
