20.19 rollout Jeff could probably tell you if you need to gear up or not. I would say you are pretty close. Maybe go up a tooth since the track is pretty fast now. The mod motor is going to be harder to drive than a 19 and will only be faster if you keep the same tight line.
The 9 should be fast enough. Your not going to keep up with quincy no matter what motor you put in the car....no offense. I ran a 9 when I went to practice and was running 10.7's with rubber tires so you should be able to get to the low 10's with foam and a 9 turn which is what everyone else was getting.