Edmund,
Yes, the full name of the standard model is First Sound Presence Deluxe Mk II 2.0. I don't know how much better, if at all, the 4.0 is over the 2.0. I have only heard the 4.0. Moreover, the F.S. linestages have many options in the sense that many people send them back for little upgrades which are offered but not reflected in new model numbers. Sometimes, it is hard to know which unit is being offered and what "version" it is. If it is older than 1 1/2-2 years or hasn't been back to F.S. in that time, it is almost certainly not current. The local dealer network, depending on where you live, may not be that deep for F.S. products, but anyway, I think the product is very much worth consideration for how it sounds. Perhaps you'll do an audition of F.S. Presence Deluxe Mk II 2.0 and let ME know how it sounds?
Artg,
I can't say whether you are being too narrow in the way that you are approaching a pre-amp purchase. For me, there are always 4 questions to ask when evaluating anything new:
1. How good can this product sound?
2. How will it sound in my system?
3. If the answer to question 1 is fantastic and to question 2 is only OK, then am I willing to make changes to my system to make it sound fantastic with this new product?
4. How much will it all cost and are the changes worth it, considering the cost?
Beyond that, I am willing to listen to anything, any technology, any price range, even if I am not willing to buy everything. To me, its the only way to learn what sounds good. If, as you say, transparency and vocals are high on your list of "must haves", I can't say how you can rule out the F.S., if you have an opportunity to listen, without trying. These are the things it does exceptionally well.
I agree that you already have fine gear and for you, the answer to one or more of the four questions may mean no upgrade or at least none that I suggested listening to.
You may find that the Ayre preamp a better match to your V-5X and your Levinson player. As I said in my original post, the Ayre preamp and amp (I listened to the K-1 and V-1 combo) did many things exceptionally well. If the V-5X is a step above the V-1, that may be very much a keeper and worth building the rest of your system around, but there is no harm in listening to other things.
Good luck.