[ardo]

I have an all-metal Tanfoglio Limited Custom by Cybergun/KWC. The slide is cracked at the point where it gets hit by the outer barrel. Could someone please help by answering these questions:

1. Are KWC metal slides made of aluminum, or is it some weird 'pot metal' composition? I have a friend who's willing to try low-temperature brazing, but he says that knowing slide's material is very important.
2. Would using a stiffer recoil spring prevent the slide from cracking? If that is the case, and since there are no replacement parts available for this gun, would compressing the spring - like putting an extra bushing in front of it - help?
3. There are spots on the outer barrel that indicate excessive wear. Would paint-stripping, filing off high spots, and polishing the outer barrel be of any help?
4. Would polishing the slide & frame rails help?

TIA.