[Combat Chuck]

No.

 

[Combat Chuck]

People are running them, but it's not a bolt in procedure.

Take a read through this to understand the scope of the issue:

2015+ STI steering rack in a 2004 WRX Wagon - NASIOC

2015+ STI steering rack in a 2004 WRX Wagon Brakes, Steering & Suspension

forums.nasioc.com

Or purchase a TSSFab crossmember to bolt it in. It won't bolt into a turbo GC8 crossmember.

 

[Combat Chuck]

I've not done this myself, but I have had a bit of interest in it. The mount points are different from GC/early GD to later GD WRX/STi, which are both different from the GR/GV racks. The cross member that TSSFab sells offers different selections for each of those, which also indicates they aren't simple bolt in ordeals. I would expect that write up on NASIOC to be much shorter if a 2015 rack bolted into a later GD WRX/STi cross member as well.

 

[Combat Chuck]

I have 15:1 racks in my GM, GF, and SG. I love them. The only point where I'd potentially want the ratio to be quicker would be in autocross. I haven't noticed even needing a quicker ratio on track, although I'm not very good at either road racing or autocross.

You are correct though, the 13:1 racks are designed for cars that aren't necessarily as inherently nimble as the GC, so I would keep that in mind. Unabomber makes mention about it not necessarily being worth the effort required to fit the 2015+ rack in an older car unless you absolutely need it to race the car.

 

[Combat Chuck]

What crossmember are you running? Is it a true JDM GC8 crossmember?

 

[Combat Chuck]

You would need an 04 STi rack and an adapter linkage to go to your steering column.