I've been considering swapping out all my stock control arms for UMI pieces as well as their front and rear sway bars, control arm and chassis braces, etc. I already have Viking coil overs at all four corners. I've read that UMI recommends for a street car to go with the rear control arms that have a polyurethane bushing at the chassis end and their proprietary delrin "roto joint" at the axle housing end. I think I also read on here a recommendation that you use spherical bushings (which I guess is what UMI dubs their "roto joint") at both ends of the arm. UMIs explanation is that the control arms with both bushing types will be a good compromise between road noise/harshess and good handling, whereas having the roto joints at both ends will be noisier/harsher. I'm looking to understand just how dramatic of a difference it is between the two options. I did ask UMI this question and they just restated the above about it being a good compromise. Also they stated opinions vary. Looking for opinions here.