This is about as simple a "minor mod" as you can get. Two pins, six screws, a little solder, and a 3mm blue LED later: Using a yellow LED behind blue lightpiping? Cheap, Hasbro. CHEEEEAP. ...Yes -- yes, I do love playing with LEDs.
This looks fantastic! I actually just bought this figure myself the other day. He and Megs really need some white border in their faction logos too. I'd like to have Bulkhead's arms swapped out too. That non-detachable saw blade is just fail.
Just a note: It might actually be easier to do this than the way I did it -- exploratory style. You can pop off the green top of his head, the green brain bucket thing -- it's not pinned on or anything -- and see the LED inside. Depending on how much slack is in the wires, it might be possible to slide out the entire lightpiping eye piece, loose the LED, snip it off and replace it, without ever having to deal with the insane wiring and gears and crap inside the chest... Please let me know if anyone tries it!