Final conclusion, my options are:
- Whatever 159
- Goliath 158 or 161
Seen the fact I didn't found the ET 157 so stable (compared to the 163 ET), I should go with the...
1/ Will the length of the board affect the dampness/stability of the board on a higher speed? Longer = stabler?
2/ Site Bataleon says: Whatever: Flex 4 / ET and Goliath: Flex 5
-> Big difference? I don't want a noodle...
Thanks for all the help man!