Intake manifold bolts loose on a Subaru STi:

Intake manifold bolts:

Also don’t forget to put new gaskets where the TGV’s meet the heads, or when you are putting those sweet new Grimmspeeed phenolic thermal spacers onto your Subaru WRX/STi. If you install phenolic thermal spacers usually in the package you’ll receive new intake manifold bolts.

Intake manifold bolts: Grimmspeed phenolic spacers. Make sure to use the intake manifold bolts that come with the phenolic spacers.
Intake manifold: Grimmspeed phenolic spacers. Make sure to use the intake manifold bolts that come with the phenolic spacers.

Grimmspeed Phenolic Thermal Spacer 8mm 02+ WRX/STI/LGT/FXT

These new intake manifold bolts are not optional to use since they are longer than the OEM intake manifold bolts. Thus, they compensate for the phenolic thermal spacers increasing the height of the TGV and intake manifold combo. If you don’t use the new intake manifold bolts you’ll run into the risk of having the OEM intake manifold bolts backing out of the heads. This will result in above video happening to your Subaru WRX/STi. When you are replacing various things on top of the engine its better to have 2 sets of hands when you lift it off so no damage occurs. Plus you will need a second set of hands to untangle and lift out all the wiring harness so it doesn’t get caught on anything while lifting the assembly off the motor and in case you’ve forgotten to undo any lines or wires.