You have an xi so your only option is the KW V3 or the H&R coilovers. For sways you can do UUC, Hotchkis, H&R, BMW in the rear, and UUC up front. The UUC bars give you a quite flat car with a safe amount of understeer that you can dial out with the V3. The V3/UUC combo is really killer, especially if you add in the Hotchkis chassis brace, but that's just my opinion
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In terms of the squeaking....yea, the V3 squeaks or pops or creaks every once in a while. I've never understood people's gripes with sounds from their suspension or sounds from their ceramic brakes....you're buying a performance part that's more often than not designed for track use, they don't care about noise
However, most of the time the V3 is silent and with enough bushing grease, the sways are as well. In terms of camber plates, it may be a good idea to pick up the KW plates from whatever vendor you pick up the V3 from since they offer a large adjustment range and are silent. I have KMAC's right now and am pissed off that I only got the Stage 2 and will be getting the KW's as soon as I can.
EDIT: Also, you can't really....match up the WRONG set of sways... I would say if you get a sway at all, get the UUC front/rear so your car isn't twisting funky like mine did with just a rear bar.