Power of the Primes Starscream custom to make him more G1-ish. The cockpit just friction holds on in alt-mode (but I don't know what I did with those pics). I wasn't concerned about the combiner mode, so I removed the second head, forearms and moon boots. I might do a coronation set for this guy later. I'm going to do Thundercracker and Skywarp with this design as well, but who knows when I'll get around to it, because I hate painting.
You did an amazing job with starscream but why would you purposely destroy his arm proportions? His shoulders are too low and his arms look way too long.
Yes, the arms are too long, but in it's original state I find the shoulders to be too tall. so I prefer him with the upper wheels removed and the shoulders against the body. Maybe one day when I'm feeling ambitious I'll design a piece to replace the bicep and elbow with one short part, but it's not high on my list of priorities.
Now if only the combiner head could be customized to be less...overdramatic? That crown is just way too nerdy for me.