I wasn't sure I wanted to go full whack with a short shifter ($ and the fact that the shifts are already pretty short), but I had some of the same issues as the OP. So I installed the Steeda shifter bracket with the harder of the two supplied bushings. The shifts are smoother, more positive, and more accurate, although care still does need to be taken. (I think I will install the Whiteline transmission mount bushing to take out that last bit of movement in the driveline). NVH has noticeably increased. Some of the new sounds are good...like the slight gear whine upon acceleration...but driveline clunks and clanks are increased and even the exhaust (I am running GT500 AB's) is more intense. I'm OK with all of this as I feel I have added back some of the mechanical soul that is engineered out of modern cars. There is also a softer bushing (that is still way harder than the OEM marshmallow) that apparently gives virtually the same improvements in shifting without any increased NVH. Overall, I feel that the bracket is a good first step for those who want to improve the shifting experience without making the much larger investment that is the short shifter itself. On the other hand, the fact that I am clicking on short shift threads means that I still feel there is room for improvement.
I did both bushings and the XL-18 additive a week ago. It definitely shifts firmer and easier. There is more noise and vibration on acceleration but I like it too. $60 for all three items is well worth it.
Received 7/2/10: 11' GT base with 3.73,
Installed: Steeda CAI, SCT, Steeda tune, GT500 axlebacks, SVT leather wheel, Infinity Kappas, Boston amp, Bazooka powered sub, yellow fog light bulbs, dark front corner lights, GT500 splash guards, tint, SVE Drift matte 18"x9" wheels with 265/40s and SVE 1" drop springs, Koni Yellow, HP+ pads, brake duct coolers with CS front lower and splitter
Bought and soon to be installed: Edelbrock E-force stage 2
Stable: 14 SHO, 10 Road Glide