I was considering a new rear bar but I'm probably going to go with a square 315/18 setup w/Falken 660s + the GM autox flash for the rear diff. I'd run in CAM-C instead of BS. I'd want to run that for a while before considering any other changes.
There's a '17 SS running 335 square Rivals, and the car is really quick! Nat'l champ driver helps a little too.
I'm getting tired of the slow warmup on the stock GYs, on a cool day it's impossible to get the tires anywhere close to competitive, and if it's under ~65F it's not even worth showing up. They do fine on a hot sunny day after a couple runs though.
Any experienced folks see an issue with that plan?