Nice choice. I am in love with my Iridiums. Please consider my 2 cents on these speakers...
I don't know too much about the Eclipse you have, but if it is 3-way capable with a fleixible crossover, I highly recommend running your comps active. They come with incredible crossovers but you can really unlock the potential of the 6.2s by playing with corssover frequencies and slopes... My car sounded best after moving the XO point lower to 800Hz/6dB LP on the mid and 1600Hz/6dB HP on the tweeters. Time alignment is especially advantageous because of the non-resonant characteristics of the mids and tweeters.
Be aware that the UR1 tweeters are pretty directional. They are soooo sweet if you can aim them somewhat on-axis. I cna't say what will sound good in your car but some experimentation will reap great SQ rewards. I actually have 45 degree tweeter pods which aim them upward and inward, between the headrests. Beautiful sounding tweets.
I've heard the UR6 set in my car as well, and the Iridium midbass alone is responsible for 3x the imaging and soundstaging of the UR6.
Good luck with your install, please keep us posted with pictures!