The sock-like design of the shoes makes them quite tight, and the upper has a lot of stretch. I removed the memory foam insole myself, and it made the shoe look much better with a clear and smooth outline over the foot.
Since these shoes have a sock-like design, the heel lining is thin, and the elastic upper pulls your foot back quite a bit, unlike the 350 where your foot tends to move forward. If you buy the same size as your 350, there will be a lot of extra space in front of your toes. For a normal, slim foot, it's better to size down by half a size, while those with wider feet can stick to their regular size. There's no need to size up by half a size like you would for the 350.
The 350 CMPCT has a lot of stretch and really presses against the top of your foot, giving a strong sense of restraint. Once you get used to it, the experience is quite unique.