Subaru STI Fuel System Plumbing - Inline Fuel Filter

Hey guys,

I've been assembling some parts to upgrade the fueling system in my Subaru since it is now completely tapped out.

Im going to build the lines myself, and this is more or less the setup I was planning to go with:

This is basically how its routed for a lot of fuel kits for this car, except fore the inline fuel filter from the hardline to the feed lines.

My question is basically whether or not I should bother trying to plumb in that inline filter as:

1) Space in the engine bay is very limited in that area with the FPR, brake reservoir, etc.

2) If you buy a pre-built kit from somewhere like cobb, they dont actually include any additional filtering.

https://www.cobbtuning.com/products/fuel-system/subaru-fuel-system-package-sti-2008-2021

However, if you check out what injector dynamics has to say about it:

https://help.injectordynamics.com/support/solutions/articles/131145-fuel-system-filtration

It sounds like an additional pre-injector filter is a must, which is odd given the cobb setup doesn't include any filtering.

Any input on this?

(Edit: Also, no immediate plans to delete the hardlines going back to the pump which I know would open up other options to mount such a filter somewhere other than the engine bay)

I trust Injector Dynamics. I've had really good success by always using a 100micron filter before the fuel rail.

There's a pump pre filter sometimes called a sock, which is for large debris.

Then there's the post fuel pump filter which is in the fuel pump assembly and catches the small debris.

The OE post pump filter in the "basket" does meet ID's sub 10 micron spec, so no additional filters are needed.

If you switch to an aftermarket pump assembly which does not have a post pump filter in it, then you would need an inline unit.