Some of this data is clear cut, some is anecdotal so I apologize in advance for not having it be more scientific. I got my P100d with all seasons on it and immediately changed to Yokohama V902B Winter Tires 245/45R19. The performance was amazing, best value ($420 shipped) I've ever got in a tire. I suspected range and noise would be bad but had nothing to compare to and they seemed the same as the all season OE tires. Come summer I switched to OZ 21's, light weight with Pilot Sport TO tires (foam in em). 245 up front, 265 in rear. My watt use went from around 320 to 360. Noise was terrible. I'd NEVER recommend these tires based on cost and noise. To do a road trip to Florida I bought a set of TSW 20's and ran a Pirelli P7 245/45/20. These gave fantastic range, 290-300 (tire size factored in). They rubbed so later I swapped the front to a 235. Efficiency wen up even higher enabling 240 on AP2 behind trucks. Returning I swapped back to the 21's and put Pirelli P zero Nero's up front in 255/30/21. Energy seems to have gone up by 10 over the Pilot sports to 370. Noise is slightly reduced. After some driving I switched the rear to Pirelli P7 in 275/35/21 as this is an eco tire. Noise went down, energy use is high but currently inconclusive as I changed brakes at the same time and it varies a lot more than it used to. I believe I'm having some issues with too much variation in front to rear tire diameter pissing off the electronics. Points to note: Handling is good but not amazing no matter what tires I ran. The difference from a 245 winter tire to a staggered Pilot Sport is not what you'd expect. Body roll is still holding the car back and no tire is going to change that. If you believe you're going to get this amazing upgrade doing 21's, you won't. They just look cool. The new brakes are amazing. 20's and 21's fit over em, haven't tried 19s yet. Tire width SEEMS to play a large roll in energy use. I'm still doing more testing. The car SEEMS to do better with larger diameter (overall) tires. I'd guess this due to electric motor power/efficiency curve. The is a decent amount of room in back for more tire, but not up front. 245/45/20 rubs, as does 235/45/20.