additional processing and customs charges on goldring 1006 or nagaoka mp150

I’m not so sure about beryllium rods being better than boron pipes. Audio Technica took a different approach, ML150 used a beryllium rod and higher end models such as ML170 and ML180 used boron pipes.

Very few cartridges used beryllium cantilevers as they are incredibly toxic during manufacturing.

Most of these cartridges are very difficult to find in good working condition and are expensive. Best for OP to get either a modern Ortofon MM or modern Audio Technica MM.

Current MMs may not have boron pipe or beryllium cantilevers, but nude stylus profiles and motors are state of the art.

BTW, Ortofon 2M range is of the moving iron type. 

Grace, Pioneer, Audio-Technica, Victor used beryllium cantilevers in their top of the line cartridges, then it was prohibited and Boron became the top choice. I’m not trying to say that beryllium is better than Boron, but Beryllium is definitely better than Alluminum or Titanium.

Density (gr/cm): 1.84 Beryllium / 2.69 Aluminum / 4.54 Titanium

Young Modulus (kg/mm): 28,000 Beryllium / 7,400 Aluminum / 11,000 Titanium

Velocity Of Sound Propagation (m/sec): 12,600 Beryllium / 6,420 Aluminum / 5,990 Titanium

Most of these cartridges are very difficult to find in good working condition and are expensive. Best for OP to get either a modern Ortofon MM or modern Audio Technica MM.

Yes, but i have spare in perfect condition, not only me, but many audiogon user have them. For example the Audio-Technica AT20SLa is about 350 euro with shipping. This is amazing high compliance cartridge. If you think the modern AT is better just read this: https://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=100109
AT-Ml170 is also available along with NOS Victor X-1 if anyone interested, just PM me. Time machine in action! 

Different engineers and cartridge designers are working in the companies like Audio-Technica, people who designed cartridges in the 70s are retired, new people are woking on the new cartridges. The situation on the high-end market today is way different than in the 70s/80s. New cartridges are not always better, sometimes it’s compromise, especially when we’re talking about Moving Magnet cartridges, the trend today is MC, not MM.

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.