Matt Wengerd (104 weeks) recently wrote a very detailed post about the many modifications he made to his Rumano Solano bass. This is an interesting post which covers many of the gear modifications that bass players in the United States are doing these days. Matt had a K.C. Strings extension with chromatic stops and was seeking a way to reduce the weight. These extensions work well but are like heavy brass weapons. I have met several players with these extensions, all of whom like the machinery with a few qualifications. They are extremely heavy extensions, which can be an annoyance (especially if you stand to play the bass).
Matt took off some of the stops and also added a carbon-fiber Laborie endpin (Rabbath is into these endpins) and removed the tailpiece. Check out this post to see photos and a detailed description of the process. He was going for a brighter sound and it sounds like he got it. His experiences with the wire tailpiece are illuminating. I have never experimented with this style of tailpiece before, but I know many bass players (especially at Indiana University) who have done the modification with positive results.