Unlike Momo, that we know he got BJK, we don't know what kind of upgrade Kaidou recieved. Momo's Bullet Serve and Jack Knife are useless against Kaidou, also both of them are rivals so they know each other special techniques inside out. Like Kaidou should easily return JK and Bullet Serve, Momo should be able to deal well with Boomerang Snake and Tornado Snake.
Then we got Momo and Kaidou's best moves so far: BJK and Gyro laser. Kaidou should have a really hard time with BJK, his wrists might not hold on that much and kaidou's power isn't great neither. On the other hand, Kaidou's Gyro Laser should be able to take some games because Momo isn't going to easily return it, also he can confuse Momo hitting Tornado Snake from the same stance and scoring points. We have to consider Kaidou's stamina which is far greater than Momo's.
Overall, I can't see a clear winner here, but I think Momo's speed has improved (seeing how he catched up to Bakyuun which is a fast shot) and he should eventually return Gyro Laser. Also, I don't see Kaidou returning Momo's BJK, mainly because his power isn't impressive, and I think he hasn't enough technique that can be enough to return it.
I think Momo wins this, but it'll be rather close. 7-5 or 7-6 to Momo.