Any more info on about the G1 custom upgrade kit you mentioned? The un-G1 headsculpt is what bugs me about Thundershred, and if I can get hold of a G1-esque one I'd be made up.
Here's a link to the thread at TFW,
https://www.tfw2005.com/boards/radicons-customs/444225-insect-add-parts.html
The thread is going to be updated with the relevant info when they're ready to take orders so I'll keep checking and post a link here when the window for ordering opens.
I think Thundershred's head is OK but the faceplate is what throws things off as the G1 toy and animation model didn't have one.