I just installed the Kartboy front and rear shifter bushings this morning. It took about an hour and 15 minutes. It was a pretty tight squeeze because I didn't drop the cross member or trans at all.
The rear bushing was a real pain to get lined up with the threads (I think that took the most time), but once it was lined up the rest was pretty simple.
However, I am posting this because I did notice a few things that were a bit odd, and I haven't seen anyone else post about them.
First, this was done on a 2014 WRX, but I was under the impression that it was exactly the same as the 2011 and 2012 WRXs. However, after removing the nut and washer from the front bushing, the large washer was just a plain washer with no notch or angled piece. I have seen a number of videos of people installing the front bushing, and they all seem to note that there is a notch that needs to be lined up, but this was not the case on my car.
Second, after getting the stock front bushing out, there was no metal bushing in the stock bushing to remove and insert into the Kartboy bushing.
Third, after reinstalling and tightening the washer and nut there was about a 1mm or 2mm left to right play in the linkage (the Kartboy bushing was slightly more narrow than the stock bushing).
But I took the car for an easy and short test drive, and everything felt fine, and much more "notchy" than the stock shifter and bushings. Definitely a great upgrade considering you use the shifter more than anything else on the car on a daily basis.
However, if anyone else has any input on the few oddities that I noticed that would be great.