I don't quite remember which heavy weapon this is from the Dark Eldar arsenal... I'm not sure it ever made into one of my lists.
By doing all the heavy combinations of the old and new kits, like the figures you have seen in previous weeks, I had more of the newer pieces available for specialty weapons such as this.
While all the individual weapons were on the sprues, you would end up short on 'regular' splinter rifles if you made all the special weapons. Not only did using the old time parts provide half a dozen extra figures per box... they had a little more interest to them as well.
Even here, I could not resist sticking one of the old head crests onto one of these "new" kits :-)