I was in a bit of a rush when answering so I’ll try to be more detailed blasphvmy .

In my opinion having a certain look doesn’t depend on single items, but more like a collection of “typical things related to the style”. If you want to achieve a grunge look,  start researching the meaning of it. Photos mostly, for this tumblr, pinterest etc can be useful. Once you have a certain image in your head, you can start building your avi. Do you want it to look more child-like or more adult-ish? Going from there, you can start picking items. I personally handle head after I tried some skins/hair combinations related to what I have in my head with that idea. I LOVE Allie heads, not jsut because they’re awesome but because comes with alot of customizable stuff (mostly due to having a mesh head version of it too). So by default with Allie head you got ->mesh heads, parted lips, two tone eyes and BUNCH OF MAKEUP VARIATIONS. Seriously, you can have green lips and purple eyeshadow while one eye being red and the other green. Endless possibilities = more room for creativity, and if there’s something you want to have and it’s not in shop, you can just message devs. Worst that can happen is them turning you down and since there are SO MANY OF THEM you can go and ask another, and another and another and so on. Back to your question, what head for grunge look, well.. since there’s no specific grunge head, you should try doing what I mentioned above. What I suggest is to have an Allie head. Everyone has it but you can customize it totally different. 

I’ll list a few heads here, try them on and see which you like most :D

http://www.imvu.com/shop/product.php?products_id=26102378

http://www.imvu.com/shop/product.php?products_id=25813245 

http://www.imvu.com/shop/product.php?products_id=29242917 I removed the lashes for less make up glitching. 

Non Allie heads:

http://www.imvu.com/shop/product.php?products_id=28900490

http://www.imvu.com/shop/product.php?products_id=27447011

(on a side note, please check what it’s derived from, and see the creator who made the mesh itself, then see the rest of the things they made and what was derived from those items they made. It’ll help alot).

Hope this helped you!

Side side note: 

skins: http://www.imvu.com/shop/product.php?products_id=28012898

http://www.imvu.com/shop/product.php?products_id=27934281

http://www.imvu.com/client.php?page=catalog_product_info&products_id=27806627