I've been looking at this for a couple years now. I finally decided what the hell lets do it. Some one has to try it sooner or later. Everyone says just buy the dam-d or prova-d but the 15+ controls and wheel just look so much better. So here we go. I got a good deal on a 2017 steering wheel hub with controls on ebay it showed up 2 days ago. I can confirm the splines do not match the 8-14's. So now it takes a little creative thinking. Originally i thought maybe buy a few adapters and cut and splice them together. Then maybe just cut the hub out of the new wheel and then weld in the hub from the correct wheel. Then it was see if the spline is pressed in maybe we could press it out and swap. None of these ideas seemed ideal. Then today while perusing ebay i found a 15-18 sti steering column for $40. I know the 15+ steering rack is a popular drop in option for the gr models so i figure they have to be similar in size and dimensions. I'm going to see if i can just swap the entire column in, i'll also be doing the 15+ rack once i find a used one. If it absolutely wont work it looks like the shaft itself is pressed in. I may try and press the shaft out and then press it in to the 2011 shaft on my car. The column is set to be delivered on the july 30. So now we wait.