Factory Wing
 

I'm not sure if this is the right area for this but move it if it's not.

I'm thinking my car needs a rear wing at 100+ it starts to feel a little unsettling. I was thinking the stock BRZ wing would give me the needed down force.

Watcha think?

I think from the looks of its angle it would give you additional down force. Whether too much or not enough, I don't know.

the stock STi wing on a wrx doesn't become functional until 117, so not sure if the brz wing will do much before that. Maybe look into the gurney flap as well if you want oem.

I'm looking for something clean.

But functional

Hmmm... I've been up to 115 on a long straight at one of the road courses here in Texas... And I felt the car was pretty stable. Maybe it's just me, but I don't think this car really needs the wing... :iono:

You can try it and let us know any difference, if you'd like...

Supposedly it reduces drag .01 while increasing downforce (unspecified amount).

I got one because I like the look and its cool it is functional.

:iono:

Does the rear or the front feel unsettled? If the front is loosing grip at high speed (a fairly common situation), then a rear wing would probably make it worse, since it could potentially reduce front end grip by pushing down on the rear (there's a lever effect). If you want really functional aero, it's important to keep downforce balanced at both ends of the car. Thankfully, a front splitter doesn't have to match the rear wing in size to produce equal downforce, so a more modest splitter may be enough.

To second what @finch1750 said, the JDM gurney flap will probably be important if you want the OEM wing to produce meaningful amounts of downforce.

Feels rock solid at 122 without wing.

This sounds like I may need to adjust my suspension. I will add a click into rebound to try and settle the car.

how much rake do you have and have you done an alignment?

115-120+ no issues

I always thought a rear wing should be used to increase high speed cornering grip in conjunction with a front splitter or dive planes to maintain the aero balance.

Wouldn't just having a rear wing make your car tight in a high speed corner? (I'm assuming it is already balanced from the factory)

On this the front feels very planted but the rear tends to want to skip around. I'm adding a front strut tower bar to try and induce some understeer.

I also haven't noticed any issues at about 120 at Willow Springs. It does sounds like it may be suspension related. You might also try playing with your tire pressure front/rear a little. Maybe add a couple of PSI to the front or drop the rear a couple of PSI.