Quick answer
Choose the 1000cc kit for moderate Subaru builds that need more headroom than stock without oversizing the injectors; choose the 1500cc kit when your fueling plan clearly needs the larger injectors. Both are top-feed rail upgrades for the same WRX, STI, and Legacy GT applications, so the real decision is injector size, not rail fitment.
Fitment is the same, so sizing decides
Both DeatschWerks Subaru upgrade rail kits are listed for MPFI WRX 2002-2014, STI 2007-2015, and Legacy GT 2007-2012. That means the chassis and engine coverage does not separate them. The meaningful difference is the included injector size: 1000cc or 1500cc. Start by confirming your exact model year and engine match the listing, then treat injector sizing as the main choice.
Why the 1000cc kit is the safer default
The 1000cc kit gives you a clear step up from stock injectors without jumping straight to a very large injector. For many street-driven Subaru builds, that middle ground is easier to tune and less likely to create low-load drivability compromises than a much larger injector. It also keeps the door open if your power goals are still being finalized. The trade-off is that if your plans grow significantly, you may eventually need to move to larger injectors.
When the 1500cc kit makes more sense
The 1500cc kit is the choice when you already know your build needs substantially more fuel than a 1000cc injector can support. Buying the larger kit once can avoid a second injector purchase later. The trade-off is that larger injectors demand more careful tuning and can be less forgiving at low load if the calibration is not matched to them. Do not choose 1500cc simply because it is the bigger number; choose it because your fueling target requires it.
What the catalog does not tell you
The supplied product records do not include flow data at specific pressures, fuel type compatibility, or tuning requirements. Those details matter for injector sizing, so verify them with DeatschWerks before ordering. If you are unsure between the two, the 1000cc kit is the more conservative starting point for a moderate build, while the 1500cc kit is better reserved for a clearly defined high-fuel-demand plan.
Trade-offs to weigh before you buy
- Fitment coverage: Both kits list the same MPFI WRX 2002-2014, STI 2007-2015, and Legacy GT 2007-2012 coverage, so neither has a fitment advantage. Confirm your exact model and engine before ordering.
- Injector headroom vs drivability: The 1000cc kit offers a moderate step up that is easier to match to a street build; the 1500cc kit offers more headroom but needs a calibration that accounts for the larger injector. If you cannot clearly state why you need 1500cc, start with 1000cc.
- Buying once vs buying twice: Choosing 1500cc now can avoid a later injector upgrade if your power goals are already high. Choosing 1000cc now keeps costs and tuning complexity lower, but may require another purchase if your plans grow. Decide based on your confirmed fueling target, not on a future maybe.
Product facts
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Subaru upgrade fuel rails and 1500cc injectors: Subaru top feed fuel rail upgrade kit with 1500cc injectors for MPFI WRX 2002-2014, STI 2007-2015, and Legacy GT 2007-2012. This is the larger-injector option for the same fitment range, so it suits builds that have already established a need for more fuel.
Subaru upgrade fuel rails and 1500cc injectors
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Subaru upgrade fuel rails and 1000cc injectors: Subaru top feed fuel rail upgrade kit with 1000cc injectors for MPFI WRX 2002-2014, STI 2007-2015, and Legacy GT 2007-2012. This is the moderate-injector option for the same applications, making it the more conservative choice when your final power target is not yet fixed.
Subaru upgrade fuel rails and 1000cc injectors
Which kit fits your build
Best for
- Subaru owners with a moderate build who want more fuel headroom than stock without going to a very large injector
- Builds where the final power target is still being finalized and a conservative injector size is preferred
Not for
- Subaru builds that already have a confirmed high fuel demand requiring the larger 1500cc injectors
- Owners who have not verified their exact model year and engine against the listed fitment