Get a 2ch preamp or upgrade surround processor

Currently I have a Proceed AVP-2 Plus 6 with a Levinson No390S (using XLR) and a Linn Unidisk 1.1 (using RCAs) for 2 channel playback (both using analog bypass). While the AVP-2 sounds great I would like to take this to the next level (but on a budget). I am looking for the wow factor (like when I went form the AVP to the AVP-2), vs. yeah I think it sounds better (in other words, a real return on investment). One option I am considering is purchasing a used Levinson No380S and running both sources as balanced. I have listened to many surround processors and have yet to find one which bests my AVP-2 in 2 ch playback. An other option I am considering is selling the AVP-2 and picking up a Linn Kisto, but I have not done an A - B comparison and I am concerned I will not gain much if anything.

Has anyone done comparison between the AVP-2 and the 380S?, and comparison between the AVP-2 and Kisto? and for that matter compared the 380S to the Kisto (2 ch)? how much of difference is there? Remember I am looking for gains in 2 channel, while not taking a step backwards on surround. Where would you invest? Or is there an other option I have not considered? Thanks in advance...
Sounds like a fun problem to solve in a system that already makes you happy! Check out the new Classe SSP-800; it has amazing HT sonics together with a killer 2-channel balanced bypass pre-amp section. If that tops your current budget, check out the SSP-600 which can be found on Audigon; it always has amazing HT for DTS and DD 5.1, 6.1 and 7.1 together with a very good 2-channel balanced bypass pre-amp section.