It looks realy good... And I hope my first diorama base, when I get to it, comes out just half as good as yours...
My suggestion for something to add is just some shrubs... As (most) of the fighting in North Africa (I assume this is where the dio is supposed to be located) was along the coast some Mediterrenean vegetation seems to be appropriate...
Congrats on a goodlooking model !!!
Harm
PS. I noticed that your wheels seem to be quite dusty. It might be the pics, but the vehicle and gun seem to be remarkably dust-free.... especially for the type of ground considered, and arguably the fact that this vehicle would not be riding alone, and therefor encounter a lot of dust kicked up by other vehicles in the convoy.
But again, I hope my models will come out half as good as yours...