Want to be a great diver, but you took Hacker as your Runner Type? You can be. Just assign a different quality to your character. Runner type rolls up all your archetypal skills into one package, but you've got other qualities available to you. These others are more specific, but they let you broaden your character's capabilities a little bit. So that hacker can be a crack wheelman too with the Street Racer quality.
However, one additional quality you get is, just like in the core PDQ rules, a weakness. In my game, I'm defining weaknesses in a particular way. They can't compel a particular behavior, but must constrain other actions. For example, a popular drawback in many games I've played is something like Impulsive, which translates into "go wander off on your own and do what the sign tells you not to do." Another that's shown up a few times is Fascination: Fire, or some pyromaniac variant, in which the character is compelled to light everything on fire.
Rather than encourage chaotic behavior, especially in situations where time's limited and we need to finish the run that same night because there won't be another session, I'm ruling a weakness in this game must constrain behavior in some way. For example, our resident hacker had, back in the SR4 days, a Strength, Body, and Will of 1. In this system he'd have the weakness of Weak. Anytime he attempts to exert himself or resist anything, he takes a penalty. I have another PC whose character comes from a rural community that's rejected a lot of modern tech, so in FTD he'd have the weakness of Luddite, for which he takes a penalty when using any hi-tech device.
These are very broad weaknesses, but given that a combination of a Runner Type and other quality can result in some impressively high bonuses, the players should still be sitting on a high pile of bonus points.