not bad,but you should have "actionmaster" in the title imho
of the three,i like how superion turned out the best.
one of the nicer actionmaster combiners i've seen so far.
the paint works and detailing is slick on all three too.
just a few things though,is metroplex finished?
his whole lower half still looks unfinished because of the cybertron metroplex stock colors still there.
the proportions are kinda weird too.it kinda looks like he's skiing now too.(maybe i'm just used to seeing metroplex as having giant thick blocky legs)
pirhanacon has nice paint,you chose a really good color combo.unfortunately i still see too much unicron/uniformity in him.the bw bits you added to him look good on the legs,but on his arms they seem kinda out of place,specifically his right arm.(the left/nautilator arm fits in good though)
edit: just noticed you used a starwars/tf snowspeeder for his chest,good choice!!
And Superion looks excellent since the proportions are so good. Nice work. 
