The red Gundam's Core Fighter.

The Core Fighter achieves transformation and docking without swapping parts!

The rack on the back is a modified part from the kit, tucked into the backpack space, and the Core Fighter docks neatly using the kit's studs. The Zeon mark on the shield was created by sanding down the Federation mold to a flush surface before attaching it and coating it with a topcoat. I didn't want it to peel off after I'd gone to the trouble of attaching it.

Core Fighter (GQ) | ケンジャ's Gunpla works