I've searched the forums but haven't found a direct answer to the following question:

Are non-sport coupes pre-wired for the third brake light in the sport coupes rear spoiler?

 

Yes, I installed the OEM spoiler in my Journey model. If you buy the OEM spoiler it comes with everything you need for all models of that particular rear. If you buy OEM Like .... all bets are off. BTW, there is no such thing as a Sports Coupe Spoiler, they are all the same except camera vs. no camera.

 

The harness connector is located directly under the trunk lid?

Where can I get an OEM spoiler third party or does it have to be directly from infiniti?

 

Some people have found OEM on ebay ... they might not be in the right color. I ordered mine from Sewell Infiniti online but I don't think they do an online business anymore.

Yes, you need to remove the trunk headliner to get at the wiring (not hard).

Frankly I would just admit it's over priced, bite the bullet and buy from Infiniti and be done with it. What you will get is all the parts and templates you need, proper fit and proper color match and a well made spoiler.