Yes, space, ram and CPU should be sufficient but the internet connection of the server matters as well.
Also I'm not sure how much taffic a 16-18 slot server will take per month.
... of course not. Otherwise I would just multiply it with 4 to get the value for a month.
Wait for the reply of someone who is actually hosting CS2D servers!
This 150 GB transfer per month is enough for 16-18 slot server with custom maps and scripts?
As Arxi mentioned.
150 GB Bandwidth is way enough for 1 Server with 16-18 Slots. You just got us confused by saying "16 - 18 slot server" I thought you meant 16 - 18 Servers with 32 slots. That would have been totally different.
and do not know how much the transfer will use the server for a week?
With customs maps and average Lua script such as TLex, it would be around 5 to 15 GB Bandwidth for 1 week of server hosting. (That if the server is really popular).
Most of the times construction and roleplaying servers are the most popular and dust+zombies are less popular (due to the zombie bots already filling the server)
-however it is a different story if the zombie server kicks bots when more players join
It's never a good idea to have huge custom maps or too many items in servertransfer, I'd say most of CS2DServer's bandwidth is wasted on stupid sfx sounds .