Well, the more I work on this, the more I bemoan the lack of detail and general plastic-blobbery of this kit. But I soldier on.
Here are the extended wingtips of the PeM-2 intended to give better altitude performance...
PeM-2-4 by
cacree, on Flickr
PeM-2-4 by
cacree, on Flickr
I have pretty much given up on the hope of extending the fuselage. The only logical place to put a plug (the point of maximum fuselage diameter) is at about the point of the wing main spar. The way the kit is engineer, this would be a major, major undertaking of plastic surgery. So, I think I'll pass.
The rest of my time has been spent cutting away plastic - from the floor of the dorsal turret, the main landing gear wells, and the dorsal hatch. Still need to do the tailwheel well.
Chuck