I'm planning on picking up one of the aluminum undertrays from TBW Performance. When purchasing one of these undertrays, they give you the option to purchase just bolts or bolts + U-nuts.

I'm missing a few bolts that hold in the OEM plastic undertray, so I already know I want to get new bolts, but what are "extruded U-nuts"? I've never heard of these. I can see that they clip onto the bumper, then the bolt goes through them, but what's the purpose? I'm assuming it serves the same purpose as a washer? Do I really need them?

 

If you have all the OEM u-nuts, then you don't need em. If you're missing a few, I'd highly suggest adding the u-nuts. I also have the TBW tray and I opted for new hardware as my OEM ones were rusted.

 

It's only $10 for all new hardware... bolts, u-nuts, clips. Just buy new and start fresh.

You know, that TBW panel is pretty appealing. I like it.

LOL at the lower front bumper in their product images. Someone isn't used to low.

 

the u nuts are wat the bolts fasten too. the tray has just holes for the bolt to go through. so the bolts are fasten without it