New DAC, or new amp?

I've got that upgrade itch. I am trying to smoothe out the sound, and get rid of some grain. I am trying to keep the spending to around $1000. I have an NAD integrated, being fed by Cambridge audio Azur 640C cdp going through a musical fidelity tube buffer. SOnus Faber COncerto speakers, and a rel sub. Cardas Cross cabling throughout. My question is what to upgrade to accomplish this goal and stay withing budget. I was thinking of ading a new DAC (MF Trivista 21). Or, should I really upgrade the integrated. Imaging could stand to be better too. Alright guys and gals.....lets hear those ideas!
This's easy, get a good tube integrated there are many available here ( A'gon ).
If you like the MF sound, try auditioning the A5 integrated in your setup! I think it would play great with your Sonus Fabers, and it should be a big upgrade overall. The tube buffer could be a source of grain too, does it really improve your sound?
Have you considered selling the tubed buffer and the NAD making room for separates? That would give you a larger budget. It should be enough in there to get a preamp,amplifier along with a Dac(if necesssary)...if you shop smartly.
I was playing with the tube buffer last night. With A/B comparisons, I found that the tube buffer makes the sound "blurry" Imaging seems better, but a little high end clarity is given up. I will probably sell the tube buffer. However, I wanted to stay away from a tube integrated. I don't like the idea of having to replace tubes, and I don't want the plethora of options by switching out tubes. I'm a real less is more type of person. Thanks.
I was thinking of buying a MF x-PSU and Xdac to augment my tube buffer and hopefully make my source a little better.
Or would I be better off upgrading the amp?