Jury is still out on acceleration. The standard version should be quite a bit slower - same power, quite a bit heavier theS will be there or there abouts. More power, but a chunk more weight. I truly doubt 20% more efficient. Edmunds rates the MINI as the second most efficient EV they have tested, after only the original Kona. A 20% increase in efficiency would make the J01 one of the most efficient cars ever built.
I'd trade a bit of straight-line speed for even more exciting handling. (Although for the first time yesterday, I actually got my car a bit sideways, attacking a tight round-a-bout at 35-40 mph. Usually I am either surprised by the no-muss, no-fuss cornering, or the car just understeers, but this time the rear wanted to break loose. For a brief moment, I thought that I might hit the curb.)
ETA: Later in the same drive, I was in the right hand lane at a light, in anticipation of turning right into a shopping center a couple of hundreds yards ahead. A pickup truck - or just a truck, if you're "true country" - pulls up on my left, then proceeds to start rolling even before the light changes, to the point that he's fully into the intersection. The light turns green and he floors it. As it turns out, he was headed to the same place, and wanted/needed to get ahead of me. I let him, then mostly caught up because, well, I could. We both turn in, he goes one way, I go another. Walking into the store, the driver (whom I didn't recognize) good-naturedly asked "Just how fast is that MINI, anyway?". I replied, "How fast do they claim, or how fast is it really?". The kicker, though, was when he lamented that he was getting only 16 mph...I then shared that it was an EV, and it was costing me only $0.03/mi to drive like that. (Well, that, and new tires probably twice as often as usual.)