Phono stage, no doubt. You will always be limiting yourself without a good phono stage, and there is a big differnece between a middle of the road one and a good one.
Almost all my lps are 30-50 years old and most have taken some hard use during my college years. I've only very recently assembled the vinyl source gear, and my goal is to enjoy spinning the lp collection I now have. I did buy a VPI record cleaning machine and record/stylus brushes.
In this context, I'll likely not upgrade beyond the Eros phono stage as I have a good supply of all the tubes it requires and its older and less costly sibling has really impressed me.
I want my revisitation of vinyl to be fun, and least labor intensive. One thing I already miss is the convenience of the vintage automatic/semi-auto tables of my youth - sonic penalty accepted (within reason). I have a refurbished Dual CS-704 on the way from Germany and may upgrade its wiring and use it with the retipped Virtuoso in place of the Roksan if its sound is acceptable. Again, mine is not the pursuit of s.o.t.a., and a well cared-for, reasonable quality vintage semi-automatic table mated to a very good and compatible cartridge may appeal to the nostalgic in me - especially spinning used lps and feeding a better phono stage that doesn't far outclass it.
I don't know if arms other than the Tabriz will drop in. It'd be nice to expand choices that don't require major surgery.looking at the picture of the Radius 5, it appears to me that ANY Rega form tonearm will be drop in compatible. If you shop for arms, they normally identify if they are Rega, or Linn standard mount (these are the 2 primary standards that have been adopted it seems). In addition to Rega, Roksan, and Clearaudio arms, Bluenote, Michell, and Origin Live arms are all Rega standard as far as I know. This leaves you many choices. I have tried the O/L modified Rega RB300, Tabriz Zi, and Clearaudio Satisfy arms. I like both the Tabriz and Satisfy more than the RB300, though there are many Rega derivatives to consider so my comparison is hardly representative of all Regas.
Thank you to all for your advice and feedback.
I will upgrade to the Bottlehead Eros phono stage and sell my Seduction, etc to fund it.
While the Eros is an unproven unit, my experience with its less costly sibling justifies my choice. I also have a nice supply of all the tubes the Eros uses, eliminating one expense. It should remain a good base from which to grow my vinyl source "subsystem", should I later do so.
As for NIMA versus Tabriz ZI/other, I'll defer for now. The NIMA has been simple to set up and synergizes well with the Virtuoso Wood. Used Tabriz arms seem to come up for sale regularly.
BTW, my re-furb'd Dual CS-704 is awaiting pickup at my local post office. Popular opinion is that these old direct drives are resistant to tweaking, but the CS-704's price was surely right given the many photos I was sent. I plan to have fun finding out for myself whether I can raise it to an acceptable performance level with modest tweaking and a few MM cartidges I have gathering dust. Again, I'd like the convenience of a semi-auto and my lps are far from virgin. "Horses for courses", as they say!