You really don't have to do anything to it. I carved the cables off the lower arms and replaced them with fine wire, added a cable on the visor and a small antenna.
The mods to the cockpit were limited to the cabling on the chair sides and that was more because I could than I had to.
My biggest compaint is the molded texture on the shoulders which would have been fin had there mot been a big seam to sand down. As a note, you'll find all sorts of 3 piece molding on this kit. Gun barrels, shoulder armor, arm parts, etc. The hinges for the cockpit armor are fragile. Just handle cautiously and all will be ok. I broke mine but was able to glue things back together.
Which brings up plastics. There are, seemingly, three types of plastics used. Some soft flexible stuff, some normal, and some hard but brittle stuff. Since finishing the build I've broke a number of fine parts (like the finger ball joints) in transit. Hopefully I get it fixed up for WF.
You'll find that there is detail everywhere. Parts that would never see the light of day are detailed.
Oh, and on the metal spec one, read all the way through the instructions before starting. Some of the PE part placement is only shown.