He has some Gundam missiles added to his shoulder-pads as well, thus resembling Ultra Magnus. I also customized the regular double-barrel handguns that are made by third-party company Dr. Wu, thus making them longer and sturdier with some household items [such as the parts taken from clicky pens and spare Gundam parts]. And I colored those new handguns, painting them black and silver. And I had to put some putty into the mouths of the new barrels, before coloring their cores gold, within the nozzle.
Additionally I gave Prime some new shoes... heftier feet created with painted putty, which can carry more weight and help to balance him more readily. A ton of nail polish was added to his legs at the hip joints, which were initially super-loose.
His standard articulation remains, but he cannot transform, since I had to glue some of his chest portions, in order to ensure that the toy would stay in position while I was tweaking it. Two shades of red were added to his upper body, and the new ultra-marine blue of his legs was also added to re-color his borrowed light-blue legs. His chest, upper arms and thighs were colored silver as well, and I also colored the circular lights on his chest. And I had to fill the core of his hollow chest with putty, before placing a plastic crest on top and coloring it silver, like a blank Superman logo placed beneath his windshields.
This guy looks very tough and rugged; and he has two extra & recolored arm-blasters added to his outer arms [one large cannon placed on the right side and and a laser rifle on the left], which both came from the "Transformers Titans Return Hardhead". Those two extra weapons were colored stone-gray and green respectively, but you'd never know by just looking at them, unless you're also a TF toy collector ;)
And since I had extras, I've also added a "before and after" comparison of some of his custom-made weapons, specifically the double-barrel arm-blasters from Dr. Wu and the classic warhammer [The Forge of Solace Prime], to show the customization results. Honestly, Prime cannot hold that new huge silver hammer. Instead, it is now fit for the hands of the Leader Class toys, which are bigger in size [as shown above]... or at least Voyager Class toys with hand articulation, so that their wrists can open up to receive the large weapon.
BTW, the former article on the guy weilding the hefty warhammer, Battle-Mode Ultra Magnus, is over HERE