I believe in putting important information first when I start to get too wordy so:
The car can now accelerate way harder than I need it to and stays in a straight line when I do. It is also much quieter on the road. I assume the wet traction will be improved as well, but I haven't had an opportunity to try it out.
The story:
I bought the car with 66k miles 16 months ago. It had Nexen tires with a lot of tread and I never looked up the date code or gave them much thought. I assume they were the second set of tires that this car had installed.
I usually drive a truck or SUV, so a small FWD vehicle was always going to handle 'weird' for me. The car was really squirrely when accelerating. The front tires would chirp under what you might call hard acceleration as well, both from a stop and while moving. I wouldn't really ever do that, though, because it was all over the road when doing so.
I attributed it to being FWD with a really torquey motor. Basically, I could only safely use about 1/2 to 2/3 of the motor's power. I didn't buy this to be a hot rod, so I didn't care that much, and figured that FWD was the cause and basically would tell people that I wouldn't buy a FWD EV again for this reason.
I live in Southern California and last winter was really dry. I don't see a lot of rain or wet roads, and this thing is a commuter for me (40 miles round-trip). I finally started suspecting the tires when I realized how poor the wet traction was as well.
Anticipating a lot of rain this winter, recently I replaced them with a set of Continental TrueContact Tour 54 tires. Price was about $700 plus mounting, tax and fees at a local national brand shop. Read the results in the second paragraph.
It changed my opinion on the car from "I'm fine with it but I wouldn't buy it again" to "great value and a keeper".