30k Iron Warriors Army Expansion: What to get next?

[Crunch1945]

Looking into expanding my Iron Warriors army and wanted some feedback on what to get next. 

Current:

About 6 squads of tacs

Chaplain, Termy HQ, normal HQ

Spartan tank

1 quad mortar

Contemptor dread

Perturabo

Cataphract terms (run them normally as tyrants)

Options:

Looking for some heavy/medium armour: Sicaran, Leviathan dread

Artillery: More quad mortars

Perhaps Iron Circle?

drop pods?

Looking at making a blitzkrieg list for IW so what route do you guys think I should run or other suggestions?

Thanks all.

[K3nn3rs]

I'd consider:

 

2 more quad mortars

Siege Breaker in terminator armour to go with your tyrants (simply use the betrayal of Calth praetor model)

Iron havocs - I'd probably take a bunker to help protect them

You can't go wrong with a Levi in a DDP

A couple of rhinos for your tac squads

And whilst I'm not sure how good they are I love the iron circle models!

[Jarkaira]

Those Iron Circle automatas are very nice looking models but only serve as a points sink as I've seen them dying easily for example against BA terminators with LCs. Also they seemed like pain to build if taking in notion how much frustrated sighs and comments the guy building them gave out at our gaming den.

 

Can't go wrong with Siege Breaker and moar Thudd Guns never.