To give the toy the Starscream look, I hyperextended the wings and glued them into position. I took the whole thing apart, painted the pieces, and put it back together again. I left as much poseability as possible, but like with Jetfire, I had to sacrifice transformation for a good paint job...too many parts slide very close together for paint to stay on.
Rather than try to rig Starscream up with a spare Space Case right arm, I exploited the similarities between his arm cannons and a loaded Cyberjet missile launcher, gluing the missile in and painting the whole assembly. I contemplated snipping off the "Q-tip" head of the missile, but eventually decided against it.
I'm marginally pleased with how the Decepticon symbols on the wings turned out, if I'd had any spare stickers of the right size I probably would have used them instead.
After making weapons out of Sculpey for my later Thundercracker and Skywarp cyberjets, I decided Starscream needed something as well. I experimented with an energon whip made from some "magic clay" that turns into eraser-style rubber when boiled, but the colors ended up too washed out after I finished mixing them, so I made an "assassination pistol" for Starscream out of Sculpey. A sort of high-tech derringer short-barrelled affair of the kind 'Screamer can push into someone's back without being noticed.