I haven’t heard the FW01, so can’t comment on that one. The FD01 is the predecessor to the FDX1. It will require modding the nozzles to sound good/great. The modding is simple and @james444 has tutorial on the forum. IME the FD01 bass is slower/boomier than the production FDX1 and I believe this accounts for the leaner faster feel of the FDX1. There is also the 1500/1800 and the Drop tuned FDW1. If you are willing to EQ, then I’d say go for the full woodies, so you can experience that unique timbre. For me, all the woodies would require a bit of EQ to be tonally good for me, whereas the FD01, with nozzle mod, sounds more tonally correct sans EQ. James444 might have other thoughts and may even have a few of these still in his collection??