How the heck can 335i have a better 0-200km/h time than 135i and 1 second faster around the track than 135i.

This is not the conclusion C&D (or Motortrend) had.
335i is on 17" rims and 135i on 18" rims, is the 17" wheels that much better. 135i is on sportchassi, the 335i is not. What a weird test.
When you check the score , AMS give 135i one point better in handling than 335i.