Not really. It's just a guitar. It is quite a thin body, so that does limit the possibilities for non-damaging mods. The neck is thicker and a lot stiffer than most standard SG necks, which does help with tuning stability.
The barrel jack is always going to be a weak point, they never seem to last particularly long without becoming a bit intermittent, so I'd suggest replacing that to give more years of reliable operation.
Arkieboy's barrel jack got replaced with a Switchcraft one, but I've since discovered Pure Tone jack sockets that have extra contacts for increased reliability/longevity and they do make a barrel jack, which is what I'd try and get hold of and use now. https://puretonetechnologies.com/produc ... arrel-jack
They only cost slightly more than a Switchcraft unit, but could easily last twice as long if they have a similar internal construction to the Pure Tone normal jack sockets.
I've extended braided cables before, and it's best to use two lots of heatshrink over the joins to prevent any shorting - one over the central cable join, then a larger diameter piece over the braid join. If you feel brave, you could go right back to the pickup itself and replace the whole cable and do it properly.