There are obviously going to be synergies with the Marsh pre. If I were you I'd start with a P2000b that you can probably get for 700 bucks or so, and then let something else try to better it in areas that matter to you. By the way, Marsh amps produce much better sound from the balanced inputs so that's the way I'd run it. Can't imagine you'd be unhappy with the Marsh pre especially since you already seem to take to the Marsh sound, and it's certainly a low-risk way to start both monitarily and sonically. Best of luck.
