im looking at adding admin mods eg invisablity, gui things liked that i have seen conflicting reports on wether or not this will take server from community to modded server. asim new to this side of things i was looking for a little clarification on this and which would be the best mods to use.

cheers in advance

Installing Oxide will make your server "modded", it's a mod. However, Facepunch allows "admin tools" only, which means only things that admin would use that would not change the visual aspect, gameplay, or other mechanics to make the game appear or behave not as vanilla to players.

its that im looking for. so installing mods for admins is ok as long as they dont change the game play eg doesnt change resource gathering.

As long as the plugin you install doesn't change Anything for rest of the players and Only for admins its ok.