Just got an sti style rear wing for 04 wrx. It's a carbon version. Does anyone know if they bounce/wobble at speed? I've seen quite a few with 'wing stiffies' and wondered if it's a common problem.

They should flex and bounce thats normal all spoilers do. I remember speaking to a guy whos a car body sprayer, he was telling me spoilers are harder to paint for that reason so the paint doesn't crack. I would say you will see it more as it's in line with the rear view. 

I'm only having the base and uprights painted, the top part of the wing is staying carbon and being lacquered. Plus, my paint shop guy has been in business for 30 years so I'm sure he'll do it right lol. Just wondering if it's noticeable at motorway cruising speeds, my girlfriend has told me I'm not allowed a new spoiler but I forgot that when I ordered it!

You can see it's not so noticeable when driving behind though, how much is the vibration from the rear view mirror that emphasizes it I'm not to sure but the Bugeye I have has a smaller prodrive uk 300 spoiler and you can see that when you look in the mirror moving around. And I'm sure your sprayer do just fine mate :) I just remember one telling me about spoilers when I was having one sprayed said it's the worse things to spray more than bumpers :)

its similar with plastic bumpers the paint needs to be able to flex a little

my last blob had a copy spoiler and it used to flex quite a lot, it just depends how smooth the road is

 

this blob has a genuine sti spoiler and it doesn't flex much at all, only obvious on bumpy roads

you can get perrin wing stiffies, but they attach to holes fitted in the genuine spoilers, don't think the copies have the extra screw holes in

Slight wobble while cruising nothing that gets on your nerves.

Just to round off this little topic and say thanks for the replies I've had my carbon spoiler on for a few weeks now. Not that I've exceeded any speed limits but even up to 120mph it doesn't move at all. Not even slightly. I would say to anyone fitting an aftermarket spoiler be prepared to make it fit. The advert says it'll fit perfectly but not the case. Took a lot of trial fits before I was happy with it and thank god my body shop guy is awesome. The other thing about it is I wasn't aware of the puddles that form on the boot now!

My genuine spoiler wobbles a bit on bumpy roads.. But wobbles quite a bit over 140.. On autobahn before any one says anything.. Genuinely as well