Subject sums it up...

My only concern with the urethane is that they may squeak? I dunno, that is just what the website said. Otherwise is there going ot be much difference between the urethane and rubber?

The urethane should be quite a bit stiffer too. I got the urethane and put some white lithium grease on it. They've been on there for about 6 months and I haven't noticed any new squeeks. Just make sure to grease them well.

Well, I can't say that I would recommend Urethane for a suspension componant. Polyurethane, maybe, but not Urethane. If you are hardcore into performance and are willing to sacrifice some comfort for that extra .5% increase in performance, then go with the polyurethane bushings. Using a rubber bushing essentially adds an undampened spring to your suspension. It isn't a huge difference, but the handling junkie who needs a fix every time he/she drives would notice.
-=B-=

That is what I meant... polyurethane. I'll probably just get them since they are the same price and all. How often will I have to grease them?

I've only greased mine once. It's been about 6 months and I haven't had to do anything. Past that, I can't say. I don't think it will be more often than once a year, if that much.

Mine are sqeaking like hell....started about two months ago. I have the Eibach kit and the greaselasted about a year now. I'm not dealing with taking them apart to grease them again, so I got the Ingalls kit(rubber bushings) that I will install shortly.