I drove a 2003 EX-L V6 5AT back-to-back with my 2006 EX-L V6 and there was a noticable difference in acceleration/power (not just torque, but upper end push as well). Some could be car-to-car variation, but it felt like my '06 had at LEAST a 15-20HP advantage to me.
I also had been driving some 2003 TL Type-S's (same day) and the '06 felt at least halfway to the TL-S accel from the '03 Accord. Since TL-S has been measured at 6.2, and the '03 Accord has been tested at 7.4, my opinion is that my '06 V6 is in the "upper 6-second range" (say, 6.7 to 7.0). After having owned a 540 (5.5 to 5.8 sec 0-60) and an '03 Maxima (6.0), I would not have bought this '06 if it hadn't felt at least close to these two other cars in acceleration.
The 6-speed V6 coupes I drove felt a little bit faster than my 5AT sedan, and had a great growl at WOT >4000 rpm the '06 sedan doesn't have as much of (and the '03 V6 totally lacked).
Just my 2 cents, but the best practice would be to hook up a GPS G-meter and go to it.
