So I started searching for this piece to only find no one carried one for the GS430. I know it is a somewhat generic piece, but it is something that needed to be purchased online and I didn't want to deal with having to return it if the length wasn't correct or the threading/diameter was wrong. So I came across a company based in Canada called Rho-Plate who had one for the IS. I sent them an e-mail and received a prompt response asking for a few dimensions. Once I sent them the info needed, within a week I received the final product.
I just installed it today and it is everything I expected. I could have made it a little more aesthetically pleasing by making it go more the angle with the bumper, but then it would not be as easily screwed on and off. Here are a few images:






The product is not on http://rhoplate.com yet, but I'm sure it will be soon.