I used a Urushi on an SME V. Now I am using a Jade on an Ikeda. The Urushi sounded fabulous but you did lose the last bit of bass. What I did to maximize the performance is use the spacer between the Koetsu & Headshell to be able to get the VTa negative enough. The other thing is I added mass to the SME V using Bluetak inside the headshell (but not into the armtube) and blue tak on top of the arm at the pivot. This advise I found on AA. It worked wonders. Truly increased dynamics and extension. IME Koetsu prefer high mass. SME V is medium but w. the blue tak (it didn't look bad at all) I had a high mass arm. I would suggest the RSP as probably the best of both worlds for the money.
Best Koetsu for SME V
I have a SME V with a Benz Ruby 2. I want to jump into the Koetsu club. What would be the best Koetsu to match the SME V. Some say that the "stone" ones (Jade-Onyx) would be too heavy for the V although there is now a new SME specially design weight to accomodate the heaviest cartridges like the Clearaudio Goldfinger at 16g. Anyway, any thoughts much appreciated. Anything Urushi and above. Gain is not an issue. I can go as low as .1mv