weight is limitation for total amount of strong things. However, if one thing that can be installed onto mech is too strong, it would break the game balance no matter how high weight it have.
you probaby did not realize, but SuperMechs is not the game about having the most powerful items existing. Its a game about making and piloting a good mech, and it have hundreds of items you can choose from. Even top players, who expert to fight only strong mechs, have a wide selection of what items they would use for their pro strategy.
If a selected few items exist, more powerful than any other in their category, top players will have no choice but to use them - or be top players no more. That would kill "customisation" part in this game - and thus, such overpowered items only appear in wildest dreams of newbies who just don't have powerful enough mech yet.
thats why no Omega items, or "Dark magic staff". You need to make ideas of something on same (maybe lower) level as currently existing items, or at least something truly new - because truly new item, even if it will be overpowered (and thus nerfed afterwards), would introduce new concept to the game.
one such an idea might be a joke... three of them clearly tells something wrong either with your understanding of game, with your common sense, or with your mind