I'd love some help/opinions

Have you considered active speakers? This is the most recent trend in high quality low distortion designs (since the early 90's active speakers have gained popularity over passive speakers for discerning applications such as mix and mastering).

Dedicated amplifiers for each speaker driver with electronic crossovers that have precise phase control etc. over the crossover region. IMD distortion is reduced dramatically since IMD distortion from each amp/driver is restricted and does not pollute the whole audio spectrum. Effective SPL ouput is also increased by about 3 db compared to equivalent passive systems. Audiophiles stress the merits of proper synergy between components and an active speaker is just that; precisely engineered synergy by a designer often rigorously tested in their labs.

Only drawback is that you may miss out on the fun of "creating" your own sound. So it depends on your main audiophile objective; is it mainly music or the fun of trying out different combinations of gear.

I'd personally plan to spend a little more for the spks. Bill

I concur with Bill.

Mike, it seems you are bent on a splashing out on a big brawny amplifier...just remember that amplifier specifications are several orders of magnitude lower in distortion compared to even the very best speakers! Finding great quality speakers for your tastes and then eventually upgrading to a suitable amplifier would be my recommended path - not the other way round.

SO if I'm looking at spending $900-$1200 on a used pair of speakers that soundstage well and are good at resolving detail, am I going to find anything better than my Snell JIII's or would I just be spinning my wheels?

I'd like to spend $1500 on the amp, $800 on the pre

IMHO, budgeting close to double what you spend on the speaker for amplification is slightly unbalanced. Try spending about the same amount or more for the speakers. I think it will get you further. Speakers are where the rubber hits the road so to speak. Differences between speakers are usually more marked than between different types of SS electronics.

The drivers in most $1500 to $3000 retail speakers cost under $100 for each speaker and are mass produced by third parties for use in many designs. Above about $3000 retail the drivers tend to improve dramatically as the labour, cabinetry, shipping and other basic raw costs flatten out and more $ is available to use better drivers. Essentially a lot of the first $1500 in construction cost goes into cabinetry and elegant veneers/finishes, which are especially expensive/time consuming but have a large impact on the look of the speaker, the perceived quality and sales. A good cabinet is of course extremely important in speaker design as is the choice of crossover but as the saying goes "you can't make a silk purse from a sow's ear".