so what wrong with your primus speakers?
If I were to upgrade I'd go with these. Friend has em and my small effient amps can push them well. I like the design and the sound, tho to me they sound "WARM" like infinity so you maybe won't appeal to your wants.
http://www.ascendacoustics.com/pages/products/speakers/cmt340m/cmt340m.html
Hmmm, I have the 163's doubt there is much difference. I guess I like the sound as I have not returned them
You could try Energy or Klipsch. They are more bright highs than I like tho. I am happy that my infinity's are 'warm' sounding. I think the warm sound makes the music a bit more smoother. I've tried both Energy take 5 and Klipsch... Booth seem highly rated but seem to cause ear fatigue after an hour so. Not much of a horn fan.
What type of AMP are you using? I just dabbled back into the tripath world. Looks like Virtue Audio has revamped it's production and is now shipping amps again. Basically a TK50. I pre-ordered one suppose to be here soon, but so far, Infinity sounds pretty good on my old trends amp.
Good Luck finding your perfect speaker! I also hear good things about BIC America but... from what I have read I think it produces more of a warm sound and I almost went with BIC DV62si over 163's but... I didn't want to chance returning speakers and I already knew I like the infinity sound... but BIC's might be just what you are after maybe they are more of a bit brighter and could be something to look into. Speakers are so hard to fit, one person can love them and others will hate em. So, trust your ears.