It's not just a track-focused Viper, but a Viper with an even better manual transmission. This makes it feel like it has more peak power than the other Viper models, for the 2010 and 2016-2017 models.
https://www.standardshift.com/forum2/viewtopic.php?t=12125
The Dodge Viper ACR also receives a new short-throw shifter in 2010 for enhanced driver experience and better performance. The rear wing profile and end plates are redesigned to further optimize the vehicle aerodynamics and improve rear yaw downforce. These changes result in an increase in top speed of 4 mph (to 184 mph).
Base Vipers trap 129-130 mph in the 1/4-mile, both the fourth and fifth generations. ACRs trap 126-127. This is only because of downforce (180mph top speed in the 2008-2009 models, 184mph top speed in the 2010 model, and 177mph top speed in the 2016-2017 model). Base Viper coupes top out at 202-206 mph (with some even topping out at 193 due to tire limitations).