My OEM chrome tip has been on all winter with absolutely no rust, even with all the salt and chemicals they use around here. Avoid the cheaper after-market tips from the various eBay vendors. They do not fit well, some do not have the rolled tip and the cheaper ones I have purchased for other cars came with set screws (not a clamp like the OEM) that were hard to get the tip tight and loosened up easily, and they rusted quickly.
You can get off eBay or amazon for about $70 delivered (Steve White Motors). Or ask your dealer to price match (most will). The OEM tip is worth the few extra $.
Don't forget to rotate the clamp to the top of the tip to hide it behind the bumper, or tack weld it in place. I have mine positioned at 1" from the bumper to match the factory placement (I measured a limited on the lot).