I bought these parts for an Epiphone Les Paul Standard as part of an upgrade I gave the guitar. They fit perfectly onto the Epiphone body and it's existing parts. (I didn't bother pulling up the lugs from the Epiphone body, I just screwed the Tonepros studs into them and they fit perfectly).
The bridge and tailpiece are of the locking variety, which is great as they do not fall off or move when you take off or change strings and are less susceptible to wobbling or slipping along the studs ruining your action and intonation over time. The bridge's range of saddle adjustment is greater than the Epiphone type, meaning the saddles can be adjusted forward or backwards to a greater extent, giving more precise intonation. As for the guitars sound, I think they have improved the sustain noticeably and made it sound a bit brighter on the cleans.
These parts are expensive, but of very good quality and build and well worth the price. I feel they give a noticeable sound improvement, but their real value is that they are a real improvement to the instruments tuning and intonation stability and save you a lot of headaches in checking, adjusting and tweaking. If anybody was thinking of replacing a damaged bridge or upgrading an old guitar or a backup guitar, I would recommend they give these parts consideration to squeeze the most out of their guitar.