All seasons handle fine but it doesn’t change the fact that if you wanted middling performance you wouldn’t have bought the sport version of the car, I don’t understand how this doesn’t translate. All seasons are middling in performance. Not good. Not bad. Putting all seasons on the car is putting the car in a situation that makes it under-tire’d. If you want to limit performance, for the purpose of saving a couple bucks, that’s fine it’s your car. But again, at that point you may as well not have bought the ST. It’s not intended as a conceited statement, it would be the same as putting a tune on the engine that limits your power so that you can save a bit on fuel. It’s just not the purpose of your car, but you are allowed to do it.
You aren’t going to see understeer with all season tires. The chassis is going to behave at a lower limit with lower grip on each corner just as it would if you had a higher peak grip tire on each corner. So it’ll feel very similar but your limits are going to be lower, and that’s a fact since you aren’t significantly altering the balance of grip ratio on either axle. I’m not telling you not to run all seasons, I’m telling you that it’s a waste and THAT is an opinion.
Additionally, I find it funny that you see importance in upgrading brakes but not tires. We could have 15” rotors with a 4 pot caliper but it wouldn’t significantly improve your ability to stop unless you upgrade the tires. This is, a form of the argument I have been trying to present: tires help with EVERYTHING except top speed. so on a performance car, it doesn’t make sense to me to get something that will limit the performance of the car regardless of how much power or how many handling mods you have. Without the right tire you can’t put down power as efficiently, and you won’t be able to stop as quickly, or carry as much speed through a turn. This is all fact and I’m not trying to sound elitist, I’m countering your argument that all seasons are enough. You believe them to be enough because you are used to the lower limits that the tires provide. Which again, I ask why buy an ST if you are just going to limit it?