If you are keeping the stock bar, get a greasable poly bushing. I believe Ford Racing has them. Just make sure you get the diameter correct, since there are a couple different sizes. They work great and feel better on hard corners.
Only issue with just replacing the bushings, you will not be able to grease them easily with the stock bracket since there is no grease fitting. You could remove them, etc., but kinda of PITA.
The FRPP kit has a bracket with a Zerk fitting and a proper sized poly bushing (think they are Energy Suspension).
Part number M-5490-HWB fit 2007-2011 GT500's.
BTW, in general, if you pump grease into a Zerk fitting, it's always wise to loosen the bolts a little to allow grease to flow more easily around the bushing.
..........and if you do go the poly bushing route, remember to also buy grease that is designed for use with the poly bushings. The plain old wheel bearing/ball joint grease gun grease is not recommended for poly bushings.
^^^^This usually requires a second grease gun for the poly bushing Silicone grease..........but a person can change tubes also if they choose. <<In this case, make sure that all of the non-Silicone grease is out of the gun and hose before you stick it on the poly zerk.