You will love this mod. I assume you're installing a Steeda (or similar) spherical bushing? PITA to DIY the stock bushing removal, but well worth the effort. The only penalty is NVH....a lot of differential noise gets transmitted to the cockpit (especially if you also run a UCA w/spherical front bushing). But who cares because *race car*, right?
No we have the BMR upper bushing per Kelly's recommendation in conjunction with upper arm. Eventually yes i see a spherical upper bushing in my future.