I would like to suggest the following changes to grant additional top speed from slipstream and DRS. This may help with overtaking a bit more.
- DRS grants 11-20KPH to top speed on average (0.333~KPH per level)
- Slipstream: If you are within 0.39seconds behind the car you gain an extra 10KPH on straights while chasing them
- Slipstream: This bonus drops to 4-7KPH between 0.4 and 1.19 seconds gap.
- Slipstream: This bonus drops to 1-3KPH between 1.2 and 2 seconds gap.
- Slipstream: This bonus stacks up to a maximum of 15KPH if gaining benefit from multiple cars.