The Part Nobody Reads Until After They Order
Most buyers shopping for an Evo X full turbo kit spend their time comparing turbos — compressor maps, trim sizes, whether to go T3 or T4 flange, twin scroll or single. That’s fine. But the thing that actually causes headaches after delivery is not knowing what else is in the box, or more importantly, what isn’t. A turbo kit isn’t just a turbocharger. It’s a system, and each component in that system has to be accounted for before you start pulling bolts.
This guide breaks down every major component in a complete Evo X turbo kit for 2008–2015 Evolution X models, explains what each part does, and flags the items you’ll likely need to source separately. If you’re buying from STM Tuned or comparing kits across vendors in 2026, this is the checklist you want open before you click “add to cart.”
What a Full Evo X Turbo Kit Actually Includes
A well-specified Evo X turbo kit covers the hot side of the engine — everything from the cylinder head exhaust ports through to the downpipe. Here’s what you should expect in the box:
The Exhaust Manifold
This is the foundation of the kit. On the Evo X, the 4B11T’s factory cast manifold is a capable piece, but it limits flow headroom as you push for more power. Aftermarket kits replace it with a tubular stainless manifold, usually equal-length with a true merge collector to balance exhaust pulses and improve spool response. The manifold determines your turbo flange type — T3, T4, or V-band — so it also dictates which turbos the kit is compatible with. STM carries the STM stock-replacement exhaust manifold as a hand-fabricated direct-replacement option for stock-frame turbos, while kits like the ETS V-Band and T4 Twin Scroll options are also available through STM for builds targeting larger power numbers.
The Turbocharger
Most full kits come with your choice of turbo — Garrett, Precision, BorgWarner EFR, and similar names are common. The turbo is typically the most expensive line item and the one you’ll spend the most time selecting based on your power target and spool preference. Smaller turbos spool earlier and suit street builds; larger turbos give more top-end headroom at the cost of lag.
The Downpipe
The downpipe exits the turbo’s turbine housing and connects to your cat or cat-back exhaust. On the Evo X, a 3-inch stainless downpipe is standard across most quality kits — it bolts to any factory cat or aftermarket stock-placement race pipe. Better kits include an exhaust flex section to reduce stress on the welds from engine movement, and an O2 bung so your wideband or factory sensor mounts correctly. STM’s own USA-made recirculated O2 housing downpipe is a popular standalone option and pairs cleanly with big-turbo kit manifolds.
External Wastegates and Dump Tubes
This is where the Evo X platform gets specific. The factory turbo uses an internal wastegate, but most aftermarket kits move to external wastegates for better boost control at higher power levels. Kits in this segment typically run dual 38mm external wastegates — TiAL MVS units are common — with dedicated dump tubes to route the bypassed exhaust gases. The dump tubes can vent to atmosphere or recirculate back into the downpipe depending on your emissions requirements and local regulations.
Upper Intercooler Pipe (UICP)
The upper intercooler pipe connects the turbo compressor outlet to the front-mount intercooler. On the Evo X, the UICP is a separate piece from the lower intercooler piping, and most kits include only the rear section — the portion that mates to the turbo outlet. This is worth confirming before you order, because the UICP geometry changes when you move from a stock-location turbo to a big turbo kit. The turbo outlet angle and compressor discharge size will differ, making the factory UICP incompatible.
Oil Feed and Drain Lines
Every turbocharger needs pressurized oil for bearing lubrication and a gravity drain back to the sump. A complete kit should include both the feed line (typically -3AN or -4AN braided stainless, depending on whether the turbo is journal bearing or ball bearing) and the drain line. STM makes USA-built oil feed line kits specifically for the Evo X, including versions sized for PTE ball-bearing turbos that require a -3AN restricted feed rather than the -4AN used on journal-bearing setups. Using the wrong feed line size on a ball-bearing turbo can oversupply oil pressure and push oil past the seals — it’s a detail that matters.
Water Feed and Drain Lines (Coolant Lines)
Most modern turbos use water-cooled center sections in addition to oil. The kit should include both the coolant feed and return lines. These are often constructed in stainless braided or aluminum hard line to handle the heat environment near the firewall on the Evo X. Skimping here is a bad idea — the turbo on the Evo X sits tight against the firewall, and rubber lines in that location tend to fail.
Turbo Gaskets and Hardware
A complete kit includes all the gaskets needed at the manifold-to-head flange, turbo-to-manifold, and turbo-to-O2 housing interfaces, along with the necessary studs, nuts, and bolts. STM’s Evo X OEM Stock Frame Turbo Install Gasket Kit covers the turbo-to-O2 housing gasket, oil drain gasket, and stainless turbo-to-manifold gasket with copper crush washers for the fluid lines — useful if your kit’s hardware package turns out to be thin.
Clamps and Silicone Couplers
Every silicone coupler and T-bolt clamp in the system should be accounted for. Quality kits use 4-ply silicone and constant-pressure T-bolt clamps rather than worm-gear hose clamps, which tend to back off under heat cycling. Count the connections and verify they’re all covered before installation day.
What’s Usually Not Included — and Why It Matters
The intake is almost universally excluded from Evo X turbo kits. This is standard practice across the industry and worth knowing upfront. The stock MAF housing on the Evo X uses 3-inch piping, which runs out of airflow capacity at relatively modest power levels. A larger intake — typically 3.5 or 4 inches — is usually part of the build budget separately.
The front-mount intercooler (FMIC) and lower intercooler piping are also not included in most turbo kits. The Evo X’s factory top-mount intercooler is replaced on most performance builds with a large front-mount unit, but that’s a separate purchase. The kit’s upper intercooler pipe is designed to connect to whatever FMIC you choose, so the two can be sourced independently without fitment issues.
The cat-back exhaust is another separate item. The downpipe included in the kit ends at a standard 3-inch 2-bolt or V-band flange, which mates to any compatible cat or test pipe and then to your cat-back. STM offers several Evo X exhaust options — stainless and titanium, single and dual exit — that bolt directly to the kit’s downpipe.
And the tune. A new turbo kit changes the entire airflow equation for the 4B11T. Running the car without a proper ECU tune after a turbo kit install is how engines get damaged — lean conditions and uncontrolled boost are the usual culprits. Budget for a professional tune as part of the project cost, not as an afterthought.
One platform-specific item worth flagging: Evo X models from 2010 onward have a plastic composite valve cover on the 4B11. Aftermarket tubular manifolds generate substantially more radiant heat than the factory cast piece, and that heat is directed right at the valve cover and firewall. If your car has the plastic valve cover, adding a manifold heat shield is a practical precaution — it’s the kind of detail that doesn’t show up in a kit listing but can save you from a nasty surprise.
A Few Things to Verify Before You Buy
Confirm the turbo flange type matches the manifold. T3, T4, and V-band flanges are not interchangeable, and kits are usually offered in multiple configurations. If you’re buying the turbo separately from the kit, double-check the turbine inlet flange before ordering.
Verify whether the kit is fitment-tested for GSR or MR. The Evo X GSR and MR share the same basic engine, but accessory routing and some component clearances can differ. Most kits cover both, but it’s worth confirming.
Ask about build time. Kits that include custom-built turbos from Precision or Garrett typically carry a 4–6 week build time from the turbo manufacturer. STM Tuned stocks a wide range of Evo X parts and ships over 90% of orders same-day, but turbo kit lead times depend on the specific turbo configuration selected.
Finally, check the oil drain routing for your specific turbo. Ball-bearing turbos require a different drain angle and flow rate than journal-bearing turbos to prevent oil backing up in the center section. If the kit doesn’t specify, ask — or source a turbo-specific drain line separately to be sure.