Top phono cartrige to match jfrech's system ...

Go the Dynavector. I have both the XV-1 and helikon. Yes the helikon is a little cool in the midrange and a little hot in the top end ( in my system).
The XV-1 to me just seems like a more musical cartridge. It seems to have a better top to bottom balance and is a warmer compared to the helikon. The helikon sounds great but I find I can listen and enjoy a lot more types of music with the XV-1 compared to the helikon. I listen to approx 85% XV-a and 15% helikon. nice to have both

cheers

I'm not sure how low a compliance cartridge cartidge you can use on your SME4. (Maybe Twl can enlighten here?) If low-medium compliance is game, then the Allaerts (above) or a VdHul Colibri could be contenders. Ultimately, a Clearaudio Insider -- if you live the "hi rez" style of upper level clearaudio cartridges.
OTOH the big Shelter (which I haven't listened to) has been appreciated in many circles. BTW, isn't Shelter made in Japan -- in which case, maybe worth purchasing there.

Dear Jfrech: As I told you all these cartridges are a great ones and all of them goes fine with the SME IV ( I alredy try on it ). But the Koetsu RSP and the Dynavector are low output cartridges and I think that the Titan goes better with your preamp because is a medium output MC and this cartridge can correct your " system weaknesses ". I can tell you that any one of these cartridges can do the same for your system. The Helikon is not in the same league, these cartridges are far away from it ( in the past I own a Helikon ). BTW, great audio system.
Best wishes and always enjoy the music.
Raul.

Jfrech,
If you're still looking, you might check out the review of the Shelter 90X at:

http://www.10audio.com

It seems like it might be what you're after. The reviewer compared it favorably to both the RSP and the XV-1s.

It's got enough output to address the issue Raul just mentioned. In fact I think Raul's heard the 90x and could give you another firsthand perspective.

Hi Jfrech: Tks Doug. As a fact I own the 90X, too, ( I buy this one in place of the 901 that I had it ). As I already told, somewhere in this forum, the 901 is in the HiFi side of music reproduction, the 90X is more refinided but still has a little touch of HiFi cartridge, is a cartridge that always said " I'm here ", it goes with the SME tonearm ?, yes but is not the best match. The 10 Audio review is a little controversial, maybe I put my feedback on it.
Now, if you are a music lover, then you deserves the best in analog sound reproduction and you have to go for the Koetsu RSP or the Dynavector, if you compare the sound reproduction of these cartridges against the live music
you will hear that you are " nearest " of this target. The 90X sound is impresive but in some ways un-natural ( I'm not saying that is a bad cartridge ). In absolute music terms the Titan, the Benz-Micro LP and others cartridges will be a really good second choice, and not because these cartridges are in second place, no, ( in some circunstances are the first choice ) this is what I think and this is my experiences. You can't have a perfect cartridge, there are many issues and facts around it and many of them are out of control, everyday live is a mix of trade-offs, and the analog sound reproduction is no exeption.
Always enjoy the music.
Raul.