My experience with Hi-Vi is limited to their planar tweeters, which are very very good. I have read great things about their mids as well. They use similar technologies as dynaudio in their mids.
I have heard a few morel tweets and liked all of them. I only selected these because of their smaller size. You could also look into partsexpress part number 279-130 which is the tweeter used in the soundstream exact component sets.
The higher resistance works out well in this case because the tweeter is quite a bit more effecient than the mids. The mids will get quite a bit more power because of the lower impedance.
Either of the amps you listed would be good choices. With the 4 channel version, I would recommend biamping your front speakers, but for max output, I would bridge it to two channel mode to maximize the power.
