What is the best turbo upgrade for a WRX or WRX STI? For a street-driven WRX or STI, the Forced Performance Blue HTZ is one of the most popular bolt-on turbos: it fits the factory location, spools quickly, and delivers a strong, usable powerband for daily driving. For bigger goals — built engine, E85, track days — the Green HTZ or XR Zero 86HTZ brings larger compressor wheels and more top-end airflow. Match the turbo to your power goals, your fuel, and your wastegate style. Check your year and model before ordering.
A turbocharger forces more air into the engine so it can burn more fuel and make more power — and the stock WRX and STI turbos leave real headroom on the table. The key choices are compressor size (bigger equals more top-end, smaller equals faster spool), bearing type (ball-bearing cartridges respond faster), and wastegate style (internal keeps factory plumbing; external gives more precise boost control at high power). Budget for supporting mods too — fuel injectors and pump, a larger intercooler, and a custom tune are required for any turbo upgrade.
Forced Performance built its reputation on bolt-on turbochargers for Subaru WRX and STI models, and its color-coded lineup anchors this collection. The Blue HTZ is the street-friendly favorite, offered here for 2002-2007 WRX and 2004-2007 STI plus a ball-bearing "LOPE" 58mm version with internal wastegate. The Green moves up to an 84mm compressor with an external-wastegate housing for higher-output builds, and the 7151S UHF and XR Zero 86HTZ with ported turbine housings serve big-power setups. Oil line kits are included where noted.
Garrett is the turbo engineering house behind countless OEM and motorsport turbochargers, and its ball-bearing technology set the standard the performance world builds on — explore the Garrett collection. TurboSmart specializes in boost control hardware — wastegates and blow-off valves that keep boost precise with a bigger turbo — see the TurboSmart collection. Browse our complete turbochargers collection for the full picture.
Shop the standouts: the Blue HTZ for 2002-2007 WRX and 2004-2007 STI, the Green with 84mm compressor and external wastegate, and the XR Zero 86HTZ with ported housing. Pair it with a downpipe and intercooler — our guide on 2015-2020 WRX STI downpipes explains the exhaust side of the build.
Does a bigger turbo require a tune?
Yes — every turbo upgrade needs a custom tune or e-tune revision to recalibrate airflow, boost, and fueling. Running an upgraded turbo on a stock tune risks running lean and damaging the engine.
How hard is it to install a bolt-on turbo?
Stock-location turbos reuse the factory up-pipe and downpipe flanges, so the swap is moderate difficulty — plan a full day, new gaskets, and fresh oil. External-wastegate versions add plumbing complexity.
Internal or external wastegate — which should I choose?
Internal wastegate is simpler and ideal for street builds up to roughly 400 whp. External wastegate gives more precise boost control at higher power, but costs more to install and is louder.
Will a bigger turbo feel slower around town?
A much larger turbo spools later and can feel lazier at low RPM: Blue HTZ-sized turbos keep street response, while Green and XR Zero-sized units trade low-end for big top-end on built engines.
