I am looking to upgrade my amp and preamp.

Lots of good reports with Aloia and Dunlavy. I use two of them in bi-amp configuration with Cantatas and, well, this is just the best combination I have heard in my set up. You can get two used for the price of Levinson or Pass new. I ran with just one amp for quite a while before adding the second one. Do search on "Aloia" in the Learn section.
I listened to Spectral, Rowland, McCormack, Goldmund, Meridian...best in my system in order was:

Goldmund 28 - too expensive though...
Aloia
McCormack DNA-225
Meridian

Be sure to LISTEN in your system. Someday I just may get the Goldmunds though...

The X250 will more than adequately drive the Dunlavys. I have a X250 with SC-Vs and they sound very good together. Prior to my X0.2 purchase, I had the X1 (mk2) and was happy enough with it to buy a X0.2 for extra balanced ins and outs. I think you'll be pleased with the combo's sonics. Low end is very tight and strong. There are amps with better soundstages, but they lack other subtle things that the Pass does right. My system reflects my confidence in Wayne Coburn and Nelson Pass. Most people that audition my system come away inpressed. But that is pretty common for most of us on Audiogon. Best Regards.

I am using a CJ MF2500 with a 16ls II and Thiel 3.6's and am very happy with the combination. I upgraded from the 17 ls. The only reason I sold it was because a friend made me an offer I could not refuse and I got a good buy on the 16ls. The soundstage this combination throws is nothing short of astonishing. I have no experience with Dunlavy but understand they are very good so I would expect a similar result.

Any of the choices you mention are excellent, but if not CJ, I would then prefer the PASS over the Levinson. Levinson has always sonded rather sterile to me (IMO). I like a tube preamp with ss amp combination it seems to be the best of both worlds. The 17ls with pass x-250 would also make a great combo.

Good Luck

Chuck