additional processing and customs charges on goldring 1006 or nagaoka mp150

Speed of sound in beryllium and boron is very similar. 

But boron could be grown around a rod and made into an extremely thin, incredibly stiff, and light pipe. 

All beryllium cantilevers that I'm aware of are rods. 

I've heard both and prefer pipes. 

@chakster                                                        My cartridge of choice for many years was a Fidelity Research FR1-mk3F (line-contact stylus, aluminum cantilever, silver coils). Used in a Lustre GST-1 arm mounted on an Ariston RD11S TT with a Hiraoka mat. Tonearm cable was Verion Traxial and SUT was a Verion P. So I know what GOOD sound is!

@chakster                                                          I own quite a few MM and MI cartridges. Empire, Stanton, ADC, Grado, B&O ... The best being the NOS Shure V15 mkV.          And I have over a dozen vintage TT's: Empire, RekoKut, Lenco, Garrard, Thorens, B&O, Linn Sondek, Technics 1200, Denon, Rabco, Marantz Linear, Sony, Yamaha, Revox, VPI, AR ...                  The Pioneer PLX1000 was a recent acquisition along with the Denon 103R.    

@chakster                                                        I also have over a dozen MC cartridges on hand: Denons, Coral, Sony, Supex, Dynavector ... 

analogueseduction.net in the UK. I bought my Goldring 1042 there.