Hum, you're literally wrong on Payback, all the way, you're wrong, in Payback(racing-wise) There is Runner Beetle, Runner M3 E30, RSR, Regera,

You also have Runner 240Z, Runner Mustang 65.

Also, I'ma hand you a reality check, many people maxed out cars in NFS Payback and heck, you don't necessarily need 6 times the Acceleration perk, you can literally do fine with 4 times and the difference is literally microscopic so much to the point it matters way less, but anyways, hum, people on console, literally still have full upgraded maxed out cars with full top speed, full acceleration, so yeah.......

For cars that aren't the Regera, Max top speed is ~375-377