I'm sure this is the bazillionth time this has been posted but I can't find the answer I'm looking for anywhere. My only question is to install GT fog lights on a sixxer, do I need a new bumper and grill?

 

yes

 

You can get the pony package, which comes with a new v6 grill (upper & lower), 2 fog lights, harness & new switch.

 

I bought the gt grill w/foglights on ebay for $150.

My detailer cut larger slits on the existing bumper slots and it fit with
some minor gaps at the bottom of the grill. From a distance can't see it.

I did not have to replace the upper or lower bumper.

 

You don't need the GT bumper. You can muscle it into the V6 bumper. You will need the GT grille unless you plan on cutting out some holes on your V6 grille...

 

To my naked eye, I cannot notice one bit of difference between the V6 bumper/grill and the GT bumper/grill. What detail am I not noticing?

 

I think there are extra tabs on the GT one that aren't on the V6 grille. The GT grille is also slightly larger than the V6 grille.

 

Spartan is dead right. The gt grill lower tabs do not align with the slots.
The curvature is definitely different. Hence, the slight gap at the bottom.
I had to remove the lower tabs.

 

Yes, +1 on the above comments. I put a GT grille in mine as well and while it did fit, it wasn't a perfect fit because the shape is different than the V6 opening. I suggest you consider a Street Scenes grille instead, you can get one that has lights in the same location as the GT grille or in the center of the grille ala Eleanor.