what impacts the sound quality more amp or pre-amp

The nominal impedance of the IIs was 8ohm with 4 minimum. I think the input impedance of the B&K amps was the odd 33.2 kohms (you really have to double check with B&K), the Mapletree get be set with 0-10db or 10-20db gain, so sensitivity should not be an issue, I do think the B&K amps had sensitivity of 1.4v, but should not be an issue with an active line stage.

The nominal impedance of the IIs was 8ohm with 4 minimum. I think the input impedance of the ST202 amps was 24 kohms, the Mapletree has 500ohm output impedance (should be OK)get be set with 0-10db or 10-20db gain, so sensitivity should not be an issue, I do think the B&K amps had sensitivity of 1.4v, but should not be an issue with an active line stage.

I checked my facts for the second posting.

It's hard to say. It really is all about components working well together. A relatively modest change in a system that contributes to better synergy can have a much greater effect than a more ambitious change that doesn't improve synergy.

One way you can be assured of a synergistic relationship between the preamp, interconnect and amplifier functions is to buy an integrated. Also, everything else being equal, you should expect better build quality and parts selection in a thousand dollar, single chassis integrated amplifier than a thousand dollar preamp, amp, interconnect combination.

I'm happy to stand corrected. Generally, I've been choosing efficient and easy to drive speakers to pair up with comparatively low power tube amplifiers. It didn't occur to me that Harbeths, for example, are relatively inefficient but remain easy to drive.

I realized that the numbers I was giving for efficiency and impedance were actually for the Alon IV. Having said that, I can't find Alon II measurements and specs. However, I did find this thread:

http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1011043701

Where at least one person says these should be tube friendly.

Personally, I'd go with a tube integrated amp, or a tube power amp with a passive preamp. You still need to pick the right amplifier of course to get the sound you want as not all tube amps sound the same and there can be striking differences between them.