Hi, I have a 2018 i3s with 20" rims. After the 1st set of stock tires I opted to use another brand with slightly higher sidewall; 55 instead of 50. Additionally I used 195/55 R20 both in front & at rear. You know front rims are a bit narrower but this width is on the limit. Having 195 instead of 175 in front gives tremendous confidence on handling & brake. The tire I'm using now is "Goodyear EfficientGrip Performance".
This seemingly small difference makes actually a big difference in vehicle comfort and driving. First of all, it softens the reactions of the shock absorbers to a noticeable extent, providing both comfort and reducing the stress placed on the vehicle chassis on rough ground. The sidewall flex in bends provides a more error-free ride. Since the inner volume of the tire expands, the same hardness is achieved with 2-3 psi lower pressure. As the tire diameter increases, speed and km data shown at the front panel are exactly synchronized with GPS data. So deviations disappear. Normally while max. speed shows 162kph, the car actually travels at appx. 157kph with its original tires. Now is 162kph for real 
This also affects the total range figures. It will seem lower, but actually is the right number.
Tire wear is much less than EP500 on these. Rear tires were dead at 37k km on EP500, E.Grip finished at 62.5k km. Front tires seems to have another 10-15k km.
Performance wise they are quite similar. Here in Turkey this set is much cheaper & easy to find compared to EP500. Best of both worlds
Strangely, there are fewer alternatives for 19" rims. I couldn't find anything up to 195, all 19" tires available on market are 205 or wider.
For the first time, last week I've started to use Goodyear UltraGrip winter tires of the same dimension with Egrips.
