Sealing with plumbing tape is pretty much the same with any gun, once you get past the various different ways that different guns are taken apart. Figure out how your rifle can be disassembled, first, then compare it to that teflon mod for the UTG M324.
I would've hoped/thought that the VSR wouldn't even get any sort of benefit from such a small tweak, but if my USR is indeed such a close copy of it, then I recommend a few winds of tape where:
- the outside edge of the hop-up rubber mates with the inner barrel
- the threads are inside the piston chamber head
- the nozel on the end of the piston chamber mates inside the outer barrel
We always hope that these things were manufactured well, but some times a little maintenance is required.
Your 120 spring should also be fine without replacing the spring guide or sears or anything like that. I'm saying it'll work fine, likely for as long as any rifle typically lives, but some times you want to treat your stuff nicely so it might last a little longer.