I dont have any personal experience with these parts on the BRZ Specifically, but I have run these on both my GD and GC Imprezas. I have always found that there is a noticeable increase in NHV, but in my personal opinion it is nothing but a positive thing. Now I do not enjoy a rock hard car, and do consider myself to be getting "a bit old" and really enjoy a nice balance between comfort and sport, and with that I think these parts would fit that bill perfectly. The extra NHV you get out of these bushings really are more of a reminder that your car is a mechanical machine with you in control, it gives you the ability to feel the car and what it is doing much better than the stock bushings, and it does this without being too harsh or aggressive. It is always hard to determine someones level of comfort, but usually I would say, if you bought a BRZ, chances are you value performance and feel over a soft plush ride, so if you do not mind sacrificing a bit more comfort, you will be super happy with these!
Hope this helps.
Thanks,
Rick