Here's my rediculously easy cut-barrel-off-bolter-replace-with-vehicle-sprue-head style:
http://i301.photobucket.com/albums/nn74/teh_perfesser/NBS001_008.jpg
I didn't invent the style, but it's ideal for talentless folks like myself. Cut, cut, drill, drill, glue head, bend wire, done.
Of course, clean, stuff gaps, pin every thing.