Changeup the enemies some. Is there a reason they're always fighting monsters? Where is the Coalition or other intelligent antagonists?
Throw them up against a CS S&D squad, or a group of Juicer mercs. Do they have any actual enemies? If not, introduce some (have a minor fight, the guy they killed? His father is a major mafia boss or other organization leader). If they have enemies, use them. Have the enemies send minions, hire assassins, put up a big bounty on the players.
Have them get stuck in the middle of a bad situation. Maybe they come into possession of something (they find it in a treasure, or some wounded guy runs in and gets shot in front of them, and they grab it because he was clearly guarding it), and it turns out that both the CS and Fed of Magic desperately want it (the CS wants to keep the FoM from using it, the FoM believes it to be a powerful weapon against the CS).
Start a rumor that these guys are sitting on technology or have a magic spell that will double or triple a Juicer's lifespan. Juicers will flock to these guys and when the players "refuse to help" as the Juicers see it, the Juicers will get hostile.
Do they owe anyone money? Time to collect, with interest, or else.
In the case where one player is overshadowing the other, I prefer to handle it out of character so there is a mature understanding and agreement. But if the player is being an ******, don't hesitate to knock him down a few pegs. Have a GB take a chunk out of his armor, an operator cripple the AI in his armor, or the AI decides it doesn't like him or gets a glitch and refuses to function, etc. Repairs are expensive, make him repair enough and he'll need to sell some things off or opt to use armor that is cheaper to repair, or borrow money from someone, see the above comment about time to collect. There are ways of dealing with it in game, but it sounds like this player wont' take that well. If worse comes to worse, sometimes it's better to find another player.
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"But you can't make an omelet without ruthlessly crushing dozens of eggs beneath your steel boot and then publicly disemboweling the chickens that laid them as a warning to others." -Order of the Stick #760