I think about moving some common subroutines from modules (StaticCode) to class.
There is no technical need. I simply want to collect subroutines together.
Do I understand correctly that similar action affects nothing, because internally classes and modules are the same (for performance, memory usage) and I will not expand Class Globals ?
The performance and memory footprint of classes and static code modules are the same. In both cases it is insignificant and shouldn't be a factor in your program design.