Is there such a thing or is OE my best option?

 

What form factor is it?

 

Highly likely that an aftermarket fit would be an only option.

 

The STR uses a different fuel pump set up from all other S Types. The pumps are very expensive at about $750-$900 each from Jaguar. There are two pumps.

Why are you replacing them? Several people have but it's not very common.
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Ditto, plus the stock STR pumps are adequate for 600+ chp.

 

1 of the pumps is starting to fail so I'm going to go ahead and replace both. About 135k miles on the STR.

Is this fuel system similar to any of the high performance fords? Cobra maybe?

 

My 03 STR has the same mileage. Wouldn't doubt the STR's pumps outflow the 03-04 Mustang Cobra.