HAT Imagine running in active or bi-amp mode are great speakers. For one I found a speaker that I don't want to upgrade any more. Good amount of detail and dynamics in the entire frequency range. Bass is fantastic for the speaker of this size. Here is a speaker you can safely high pass at [email protected]
, run good power to it and have it sound good, unless you're playing test tones. Tweeters are detailed and never harsh. Some people described tweeters as harsh, but they were running them in passive mode. Run these in active or bi-amp mode with a 2.2uf capacitor for tweeters high pass and gains carefully set, and these tweeters can be tuned to sound better than most passive components. In order not to sound as a complete HAT cheerleader, I will note that mid-range sometimes gets harsher at high volume level. On some recordings female voices become kind of peaky and sometimes harsh to my ears. It seems like reducing the 1KHz output by couple dbs fixes this, but that's not 100% satisfactory to me. I want to get hold of an RTA setup to investigate this issue. Some poster mentioned it's primarily due to car specific reflection issues.
Unity is very similar to HAT Imagine. The woofer is the same, except that there is a dust cap instead of phase plug. The Unity tweeters and passive crossovers are coming from the higher end HAT Clarus line. If you have under $350 to spend, I vote Imagine to run active or Unity to run with passive crossover. Here is a recent review of Unity speakers:
Hybrid Audio Technologies Unity U61-2 6in Two-Way Component Speakers - Speakers - Talk Audio Online Car Audio Magazine & Forum - Talk Audio Online Car Audio Magazine & Forum - Magazine (http://www.talkaudio.co.uk/index.php/index.html/_/reviews/speakers/hybrid-audio-technologies-unity-u61-2-6in-two-w-r1262)