To be honest if you want to feel more torque even a big ass 6380 won’t be much different than a 6355 as long as you ride on flat surface. From my experience bigger motors won’t give you faster acceleration, they will give more torque only so I’d be noticeable when riding up a hill, launching from a really bad terrain or launch better when off roading, I’d also help if you are a big buy 120kg or so. Bigger motors also have the disadvantage of more weight.
If you are looking for faster acceleration then upgrade to 12S, that’s is really an amazing upgrade, cheaper than a set of new motors.
You should try to get 60km/hr final speed on your boards, use the esk8 calculator and select from you hardware from there.
Once upon a time I wanted the board with the highest torque ever, I went down to a really torquey pulley setup and a reeaaaaly low final speed, 200kv 6384 motors, 12T motor pulley, 72T wheel pulley on 12S battery and 200mm pneumatics, I though it was going to be a fun board, the launch from a dead stop was a little better but the overall riding experience sucked balls, the peak torque was too narrow on the powerband, just a glitch of full torque, the top speed uncontrollable when lifting the throttle, top much drag up top, the small motor pulley skipped like mad.
So my final word on it would be to look for 60km/hr final speed, use 14T wheel pullies minimum, choose the correct motor size not for the acceleration but for the battery discharge current capability and consider weight, 12s has a bad reputation but gives you plenty of power to play with, all my electronics have been working fine on 12s for a really long time in everyday abuse.
Hope I could be of some help to people around here trying to choose their hardware