Metroplex's Minicon is called Drill Bit. Drill Bit is very similar to the old Leader 1 minicon that came with Megatron. It shares no parts with the previous toy and is somewhat bigger but Remy has some pictures that show how similar they are. The Major differences between the 2 toys are that the cab now points towards the drills/guns/robot legs (which makes sense if they are drills so the pilot can see where he's going - See Destruction team Drillbit) and the minicon socket is mounted on the top side of the toy instead of underneath it.
As I mentioned above the Minicon port is now on top of the toy - finally another minicon suitable to go under TFA Thrust's wing. For any other Minicon post mounting you're going to get the robot's head and chest looking out at you. Like Leader-1 he can be stretched out to form a dual cannon that can be arm mounted.
TF: Fold the drills back and then stretch out the limbs they're attached to. Swing the front mudguards and exhausts round to form the arms.
Robot is so similar to Leader-1 that I'm reaching for the copy & paste here ! The robot mode bends at the knees and the hips & shoulders turn. That's it for articulation. The Minicon socket is better placed than on Leader-1 in robot mode - it's on his back instead of his waist. You can see most of the colours on the toy here. The drills are hidden - but coloured blue like the wheels (and Metroplex's body), the upper legs are a bright blue (Metroplex's shoulders and antennae), the arms & the lower legs are grey (Metroplex's shoulders again) and the body & head are black (like Metroplex's head).
Yes the design is effectively reused. But it works well enough, some of the modifications make sense (cab, Minicon port in robot mode) others (Minicon port for mounting on larger toys) less so.
In Japan Drill Bit was called Horri-Bull and came with Megalo Convoy (Metroplex) and a chromed version of the Legends Of Cybertron Optimus Prime (Galaxy Convoy). This package was numbered GC-23 and was the last Cybertron Galaxy Force toy to be issued.