With those points you could buy 2 ravagers, or spend 30 more and buy 2 razorwing fighters/voidraven bombers.
I always do two things while making a list: fill heavy support and take as many troops as possible, then fast attack, elites or another HQ are next to fill the list.
Adding scourges seems pretty ok, but I wouldn't go for the 4 special weapons, é is just fine with a few scourges. Wasting splinter shots isn't a big deal as you probably have tons of them elsewhere, you don't have enough anti tank, this makes any anti tank weapons very useful.
For now here are the possiblities I see for my scourges:
Numbers between 5-8.
-full carabines, no upgrades, just full anti infantry. reminds me a bit of my eldar Hawks.
-2 special weapons, any kind.
All have their advantages, blasters and heat lances are closely the same.
DLs are also quite good, no moving, but rapid redeploying, as well as staying at logner range, the further away you stay, the safer you are.
Blaster isn't better, because when you get closer, you also expose yourself a lot more to danger. Seeing how we lack DLs in the new codex, taking scourges with 2 DLs doesn't seem that bad at all. I'm thinking about a splinter/DL spam with trueborn and scourges with DLs next to some ravagers and lots of warrior squads, close to the lists we had in the odl days, except trueborn and scourges would provide some DLs we lost.
SC are quite good, though only one more shot, taking 4 SC doesn't seem worth it, seeing how much the entire squad will cost.
upgrading a leader doesn't make any sence in this unit.
BTW, 6 scourge with 2 heat lances or 2 blasters cost exactly the same as a reaver, mobility is close, reaver just have the turboboot and fly by attacks.
Scourges make up for the loss of those things with beter armor and better firepower.