Thanks for the responses, guys.
Totalsonic - I should have said in my original post, I already use good pres - DAV Electronics Broadhust Gardens, as used at Decca. One issue with these is that they have a massive output, which clips the mixer if I don't use the mixer's pads. However, the pres do have a really big, open sound, which I like.
Rich - I'm using MK5 capsules and have been mostly recording a pair of acoustic classical guitars in ORTF. I'm not disappointed with the results I'm getting as such, but I want to take my work to the 'next level' (or the one after that!) and i'm just looking for the best tools for the job. I don't really care about portability (within reason).
When you talk about getting the pres near the mics, do you literally mean a short length of cable between mic and pre? I do record at 24 bit, but what does it mean to dither with Powr-3? (I currently use Logic's dither function).
Also, Rich, which Sound Devices unit are you referring to?
Thanks again.