Hey there, fellow gearheads! If you’re diving into an engine build or just looking to give your Subaru STI a solid refresh, you’ve got to check out the GrimmSpeed EJ25 Head Gasket Sets. Seriously, these gaskets are a big deal in the aftermarket world, and for good reason.

First off, let’s talk about what makes these gaskets stand out. They’re crafted with a multi-layer steel (MLS) design that’s tough as nails. This construction means you’re getting optimal sealing for both the surface and the combustion chamber when you torque them down. Plus, the top and bottom layers have a Nitrile Rubberized Coating, which is a fancy way of saying they can handle a rougher surface finish—up to 50 microinches. This helps seal those tricky, non-critical areas that can sometimes be a pain to get right.

One of the coolest features? The gasket edge has a folded stopper layer that really locks down the combustion chamber. This is a game changer, especially if you're pushing your build to the limits. High cylinder pressures can be brutal, but these gaskets are built to withstand it and minimize the chances of failure due to combustion gases sneaking through.

Now, I know how important it is to have the right thickness for your specific build. That’s why these gaskets come in three different thicknesses—0.78mm, 1.1mm, and 1.5mm. This variety allows you to fine-tune your setup, whether you’re just refreshing your engine or building a high horsepower monster. And if you're looking to go a bit bigger, the slightly oversized bore diameters accommodate up to a 0.5mm overbore, which is pretty handy.

Another neat detail is the enlarged center head bolt holes, which are designed to fit up to 13mm head studs. If you’re planning on cranking up the power, this upgrade is a must for ensuring that extra clamping force you need.

To sum it all up, the GrimmSpeed Head Gaskets are a solid choice for anyone serious about their Subaru STI from 2008 to 2020. They carry the quality you expect from GrimmSpeed, and trust me, you won’t be disappointed.

• Sold as a Set/Pair - Fits both Single and Dual AVCS configurations
• Die Cut Multi-Layer Stainless Steel (MLS) Construction - Consistent quality with a manufacturing tolerance of ±0.001''
• Folded Stopper Layer for better sealing in the combustion chamber
• 0.25 micron Nitrile Rubber Layer Coating - Reduces the chance of leaks on less-than-smooth mating surfaces
• Accommodates up to 100.0mm bore
• Compatible with up to 13mm, 1/2'' studs
• Available in 0.78mm, 1.1mm, and 1.5mm thickness (after crushing)

Fitments:

• Subaru STI 2008-2020

So, if you're ready to take your build to the next level, grab a set of these gaskets and get to work!