I have one of the WLG Wirblewinds on the paint table right now.
As others have said, the hull is a bog standard resin panzer IV ausf.H and includes gun cleaning tubes for the 75mm and left the motor gear housing on the rear.
There was quite a lot of work to get the hull looking right, but overall, now correct, it is still very basic detail.
The Wirblewind and the Jagdpanther are the 2 models i am now most looking forward to.
Having said that I am also wanting 3 decent Panzer IV ausf J which should (I hope) be available soon.
Cheers
Tim