Perks
Enhanced Autobash
This ability increases the number of characters you can run into while in high profile without stumbling. This is useful when you're in chase or pursuit mode and any slow down could result in failure. The difference between this and just holding B as you run to shove, is that shoving slows you down slightly.
Blender
The Blender perk changes one character in a group to your character skin when you blend in with them, unless one of them already has the same skin as you. This is a good way to quickly fool a pursuer you know is close to you without wasting one of your abilities to disguise yourself or morph the whole group.
Streak bonuses
Streak Bonus +100
This bonus is applied once you have killed three targets in any manner. The bonus adds an additional 100 points to your score for each successive kill until you lose a contract.
Streak Bonus +300
This bonus is applied once you have killed three targets silently (you will see the Silent score). The bonus adds an additional 300 points to each successive silent kill until you lose a contract or kill a target without the Silent bonus. I'd recommend the streak bonus because it is highly unlikely you'll get 3 kills in a row without being noticed.
Extra Sensitivity
This bonus will increase the precision of your compass until you make a kill.
Reset Cooldowns
With this bonus active, any abilities currently on a cooldown timer will be reset every time you die, until you make a kill.