I just checked and yes it will possibly take more computer resources. Whether it is acceptable or not it is up to everybody.
From my own really basic estimates, Rainlendar v2 is already taking up more resources than the original one (approx 11 megs with the default configuration compared with 3 megs with the previous version).
Once I install my remote calendars and local tasks the memory usage goes up to 19 megs.
The memory usage could surely be lowered but for now it doesn't slow down my system and with all the added functionalities, I'm not the one that will complain.