Please do. Sounds like they were talking about a springer - the SDiK comes with its own guide rod and cylinder head. Removing the GSpec cylinder head means knocking/drilling through a ⌀~3mm pin. I've never done it myself, but from the looks of the video Shizbazki did - I'd PM him on here maybe.
Edit
As Shizbazki demonstrates in his video: The whole of the cylinder internals are removed. In the video you can see he's using a 90o trigger, piston, aftermarket spring guide and (probably) spring - none of these are necessary in the SDiK, but he was running a spring-powered build beforehand so rather than have to switch back to the old trigger he picked up the 90o SDiK kit. I imagine he either sold the piston, guide rod, spring, cylinder and cylinder head or kept them for another project.
The standard 45o sear/trigger mechanism has a small surface area which is holds the piston back with until you pull the trigger. The point of the 90o sear engagement trigger/piston combination was to give more surface are and reduce wear on t he sears - this is important for use over 1J in a spring-powered build as the Marui design was made for sub-1J use. Lots of people just go and throw new spring in and 3 months down the line their sear rounds off, or the piston snaps and their gun is broken.
However, the SDiK kit doesn't use spring power - it has a very short spring that's actually about half the power of even the stock Marui one that the 45o sear engagement was designed for. This is because the job of the spring is only to actuate the valve that releases CO2 or HPA and isn't the power source itself, so it can be very small.
That's why I say the SDiK route isn't as expensive as people may first think: You don't need a 90o trigger, piston, spring guide, spring, new cylinder or cylinder head, because it has no effect on the operation of the SDiK. Again, the idea of the 90o trigger and piston is to add longevity to a high-muzzle energy spring-based build.
Yea I searched everywhere and can't find the post now, not even sure what forum I had read it in. Forgetting about that though, if I get my TM VSR and its crimped and I'm going to mancraft it then what exactly will I need since I won't have access into the cylinder?