Everyone probably knows about this, many made a big deal about Glamorus being a total carbon copy of that Luxurious remix. But it's not really, so finally here is the history behind it:

But then late last year a “Zone 4 remix” attributed to Polow Da Don began circulating that found the possibilities that the original producers had missed. Polow melded his rap sensibility with all the charms and cheese of freestyle and new wave to transform “Luxurious” from a 3PM breeze to a 3AM banger with double-time claps, comedown stings and an electro-processed verse from Ludacris. Stefani, of course, turned it down.
Although Polow’s version of “Luxurious” never saw legit light-of-day, he professes that everyone—and he means everyone—said his take was better. “[Interscope Records head] Jimmy Iovine told me he was feeling my remix,” Polow recalls. “But I guess when he tried to convince Gwen to use it she said that it reminded her too much of some song from the ’80s. Though he said he didn’t know what she was talking about.”

...

He also says it looks like former N*Sync member JC Chasez will give a home to the beat from the “Luxurious” remix. Only JC Cheeze didn't take the beat – for reasons unknown to us – and so Polow applied it when producing Ms. Ferguson.

oh, so that explains it all