hi Rob,
your Shilka looks very nice and the paintwork of the camo brings out the uniqueness of the vehicle subject. photoetched brass is a different material to use than most other scale products and it does come with tricks and tips that can be researched online. one tip i can give is to cut the brass off the fret on a hard surface (i use an old piece of glass) so that the brass doesn't bend during cutting. you can also put the fret on a piece of tape so the piece doesn't go flying when it is cut free.
i use tweezers for most of my bending, i get them from the cosmetic section of the grocery store. i highly recommend annealing the brass for curves, bends and doing damage. this just involves putting the brass over a burning matchstick (hold it with tweezers) and then clean it with soapy water and you will see what a difference on how the metal behaves.
years and years ago on a far away planet i built the Shilka (was it the late 80's or early 90's?) and there wasn't any PE brass like there is today. but i got Concord's book on the Shilka and built a full interior, driver's compartment, generator compartment, ammo feed racks and lots of details from plasticard and stretched sprue. here's some pics:
things you may want to add are the wires running to the radar array, rain caps with drawstrings for the barrel ends and the cooling hoses on the barrels made from copper wire to make them look less stiff.
my model shows many rookie mistakes but it was fun to build and i hope it helps in some way to add it here. cheers, bd.