So having 17 in. wheels with a bigger sidewall (MT drag radial 295/45/17) will give me more traction than a 19 in. wheel that is wider ( MT drag radial 305/35/19)? I am at about 400 rwhp now and don't see that increasing a whole lot for the next few years.
A larger sidewall allows the tire to "flex" which helps maintain traction. I've seen people hit great times with 275s on smaller wheels. I personally would take the extra sidewall over the extra 10mm in width, but I would also dedicate that set of wheels to the track.
I don't know if the smaller wheel will buy you any more traction at those power levels though. I think @84Ttop suggested that 19" wheels will probably be ok.
I drove around on my new wheels and tires. The taller tire very much tamed down the car. It actually feels like it has better drive ability with the taller tires. I'm on 315 35-20s at 70 the car reads 5 mph too slow and the headlights are no longer aimed correctly
2016 Gt stock automatic. My best times were 13.04@108 and 13.05@109 with 2.0 60's. I wasnt sure what to expect 1/4 wise but Im happy with the trap and the 60ft. Cant wait to throw on some mods and go back