Oem size: 195/55/15
Track size that's close to rolling radius: 205/50/15
People who want a cheaper alternative: 195/50/15 but this size has a smaller rolling radius and will increase your mileage.
I've actually used the last size for tyre cost reasons.
rainsports are fantastic if you want a multi purpose tyres, i.e you want to actually drive reasonably quick in the wet.