ORIGINAL: P Zero

ANy time you replace ANY suspension component, it NEEDS to be greased with SILICONE LUBRICANT. If you put it together dry, it WILL make noise. 1 more thing and probably the MOST important, when changing control arms, is you MUST set the car down on its own weight, otherwise the bushings will bind in the position theyre tightend in and literally shear the bushing from the metal its connected to, then your car will hae all sorts of weird wandering problems.
BTW, they do make aftermarlet FRONT lower control arms, I have Ford motorsport ones on mine, they made a huge difference in cornering capability. I think theyre worth more than any rear ones you get.
-P.