Nagaoka MP-500 cartridge

Maxson:

In terms of MMs, my current fave is a Shelter 201 w/SAS stylus. Signet TKLca is a top performer as well. I'd put the Nagaoka on a tier below that, along with the AT-50ANV.

Is that SAS stylus still available for the 201? Which stylus is it--the one for the Sumiko Pearl? Also, did you mean the AT150ANV? 

Maxson: Thanks for the info. How did you know the SAS-1 would fit the Shelter 201? I have an AT150MLX, which comes standard with the boron cantilever (like many Nagaokas) but the AT150ANV has a sapphire cantilever like the SAS-1. The boron replacement stylus for the AT150MLX runs about $258 but I notice that the Jico SAS-1 with sapphire cantilever is $211. Strikes me as a relatively good deal. 

I picked up a Shelter 201 just to check it out and I'm pretty impressed. I take it that the SAS-1 replacement stylus noticeably elevates its performance?

Thanks in advance.