Hey Peter,
Yes, you are right. Joomla sites face constant intrusion and hacking attempts because of the insecure codes. However this is not the case with our servers as mod_security rules on our servers filter such invalid arguments passed by the intruders.
There is no need to install any Intrusion Detection System as we have already updated the mod_security rules on our servers. However, if you want to install any IDS on your VPS then you can check he allocated resources and the resources that IDS will consume. Accordingly if the allocated resources on your VPS are enough for you to install IDS then you can install it with the remote access. Again, I am not much sure if this will be possible on VPS as well because IDS system may require more resources which will affect other users on the node. If you want to install your own IDS then I would recommend you to consider our Dedicated Server where you can install any applications you wish to use.
Hope that helps!
