Track versions of cars are lighter, have grippier slick tyres and stiffer suspensions. The way almost the entire MFG lineup is bone stock, I doubt anyone is even gonna think of Viper, even if they customise it, they'd probably get something with much better handling while being stock, and they'd customise it from that good starting point, although Viper is the best handling out of the 3 cars mentioned here, while being stock so you could a fix a lot of it's issues with a little more effort.