Preamp w/ a budget of $2000

VTA - http://tubes4hifi.com/

They sell everything both in kit form and preassembled.  Their top line line stage preamp, the SP14 sells for $1350 preassembled and for $960 in kit form.  Their best phono preamp sells for $895 preassembled and for $650 in kit form.

There's a used VTA SP14 selling for $800 at the US Audiomart website.

http://www.usaudiomart.com/details/649355979-tube4hifi-sp15-tube-preamp/

A CJ Classic 2 SE w/Teflon caps selling at Spearit Sound for $1999.

OP, coincidentally I have the same preamp and was/am in the same quest as you are. The usual popular choice in preamp upgrade path is Conrad Johnson and I watch the classifieds and read as much as I could to find a good choice. I had the opportunity to borrow a CJ Classic 2 (not SE) from a friend and used it for two weeks. Even though initially I really liked the CJ lush sound, at the end, even to my own surprise, I much preferred the NAD. I found it more balanced and seemed to cover a much broader range, top and bottom in particular. I have no doubt the higher model CJ preamps or even the SE model(s) sound better but don’t discount how good this particular NAD preamp sounds. And yes, it does run hot and I assumed it had to do with its Class A gain stage. All I’m saying is try to listen to your options if you can before dumping the NAD, especially if you want detail and prefer a more "clinical" sound. Ironically, I was looking for something with a less clinical sound but realized clinical and balanced kind of go together, at least to my ears. Of course the equipment synergy also needs to be considered and maybe in my system this preamp just sounds better than a comparably priced tube replacement.

@bensturgeon 

Hi Ben,   Looking at all of your comments, it looks as though you are not looking for Tubes... don't get me wrong there are tubes out there that can have the detailed sound,  but they can be costly and at your budget, I believe that SS will solve the problem... Here are a few pieces that I believe could solve your problem. 

Rowland Capri or Capri 2 (1st mentioned)
T+A Elektroakustik 1230R
Classe CP60
Muse Model 3 Signature

I have the VTA SP14 preamp for sale on US Audio Mart.   Don Sachs has greatly customized the basic SP14 and has one for sale at the moment for under $2K.  I have that same amp in my main system and it is the finest preamp I have ever heard in my system.  It has a remove control.  Google Don Sachs Consulting and check out the Line Stage link for more information. Mark