Ratgard have released their Hedgehog Anti-Aircraft Weapon System kit for the GW Imperial Guard Chimera.
From their announcement:
The Hedgehog Anti-Aircraft Weapon System upgrade kit is the second upgrade kit produced by Ratgrad. It comes with removable radar cover, and fixable/adjustable main gun elevation design.
This upgrade kit comes with 31 pieces of resin parts. It is 100% compatible with Imperial Chimera IFV’s. (Also compatible with Ratgrad’s Sciuridae upgraded IFV’s.)
This set is 48$, and 10$ shipping to the worldwide, you can contact me with firstname.lastname@example.org.