Stele's pilot ability marries up perfectly to the Advanced Targeting Computer (ATC). Sneaking a critical hit through and then selecting which one out of a possible three can really spell doom for an opponent.
At pilot skill 7 he isn't the sharpest activation around but thanks to either Veteran Instincts or Adaptability he can increase to a respectable 8 or 9.
Calculation isn't a bad upgrade card in a pinch but it isn't urgently required because of the ATC. Crack Shot can be used to ensure that critical hit gets through at the right time however if you have the points, then invest in Juke.
A Score To Settle provides a zero point EPT for Maarek Stele to take advantage of his ability, however its only against one ship but it is powerful and has great synergy with his ability being free.
If you're after 4 more green manoeuvres to put to his dial, then Twin Ion Engine MKII is a steal at 1 point.