soft dome or hard?

Well whoever told you "silk is uneven" doesn't know what they're talking about.  Silk dome tweeters are perhaps the most accurate and musical of all dome tweeters, although they may not be the best choice in a car.  A "soft" dome tweeter is one where the diaphragm is generally made from some sort of fabric, and a "hard" dome tweeter is generally made from metal or plastic.  You cannot change them from "soft" to "hard" or back.  Soft domes are generally smoother and have a more gradual roll-off at the high end.  They tend to retain their shape better than hard domes and are more accurate.  Hard domes tend to place more emphasis on the upper frequencies and often have extended response above the range of human hearing (this often is interpreted as "harshness" by users.)  They are sharper and sometimes more prone to distortion and cone breakup, but they tend to project more than soft domes.  Hard domes are often used in cars since their more present upper frequency response and sharper sound tends to "cut through" road noise better.  The preference of one over the other is usually subjective and personal. Support the12volt.com

I agree with what DYohn said, but just want to add this:  If you're considering those rather expensive drivers, you probably aren't afraid of spending money on a couple bands of nice parametric eq.  A little notch here and there and you can adjust for much of that harshness.  My advice is to pick the set that is closest to what you're looking for, you can always make minor adjustments later.  Or keep looking... the hunt is half the fun.  New Project: 2003 Pathfinder