Basically after the IG's you need 2-3 ships and you can play pretty competitively already. Not every ship can claim that!
2 IG boxes
1 starviper box
2 B wing boxes \ 2 Ewing boxes \ 2 lambda boxes
2 kihraxz boxes \ 2 defender boxes \ 2 Awing boxes \ Imp Ace box
т_т
yeeeah, 2-3 ships
Okay, so you need 5 ships at most. I would probably go 2 Kihraxz which are not lost for a Scum player for (PTL or Predator) and then Advanced sensors or FCS. If you took 2 shuttles you would get Sensor jammer on top of that! It's bad coincidence (or not...) that no ship gets a useful EPT/Systems combo for the IG
Now which other competitive list needs less purchases. Not many!
BUY A WHOLE FLEET!111