We get many calls for upgrades on this model, as a guide to assist you we have created this list to save your time, guarantee your money is invested correctly and most of all give you maximum value!.
SUMMARYTypically this car is a "Subaru's peak performer" and a high performance car. Treating it like a basic road car and not maintaing it correctly will result in future costly repairs an maintenance.There are some great features of this car, revised looks (compared to past model), 4wd, turbo 2.5 litre and most of all, a sensible budget with some well planned upgrades and it turns a great performance car into a super car beater!
ENGINE WEAKNESS'sPerformance can be dramatically improved with ECU tune. The engine is detuned and also limited due to emisions requirements when delivered by the factory.Poor durability with the factory standard Hypereutectic pistons can be troublesome. Poorly designed upgrades only magnifies the risk of piston ring land failure that results in high oil consumption due to cracks in the piston skirt. Run too much boost or too much ignition advance and the result will inevitably be piston failureBoost and VVT cam maps, can be improved. Car MUST be run on 98 Ron Fuel unless a custom (ecuteK) map is done.The turbo is reliable, but if over boosted with boost controllers etc will result in costly failures.Be careful with increased boost on this engine, poor tuning or lack thereof, will significantly increase risk of piston failure.
ENGINE SENSORSOn this model the aif flow meter sensor is same and just as reliable as the previous model, but can suffer contamination and in turn this will effect reliability and performance. (see MRT for this solution)The twin rear exhaust O2 sensors if located incorectly related to modified exhaust can cause problems, if old can also dull the cruise performance of the car and increase fuel use.Crank, cam and Knock sensors are reliable, but with age can fail.
FACTORY ECUCan be converted and fully tuned, using EcuteK Software for almost any improvement and allows solid, good value results with correct settings and allows good improvement.The ECU in this model can also be upgraded to "EcuteK Race Rom" for added features that were never included in the Subaru ECU.there is no need to replace the ECU on this model.
INTERCEPTOR ECU OPTIONNot worth considering as the intercptors simply do not have eniugh options to tune and modify the latest technoplogy control inputs.ZERO VALUE
NEW (replacement) ECUFactory ECU retune is best value unless a really serious engine rebuild is chosen. (IE over $25k) replacing the ECU with an aftermarket unit is not needed as long as your tuner has the correct EcuteK softwareSee notes above
INTERCOOLERFactory fitted unit is huge and hard to beat, comes with silicone connector pipes.MRT replacement TMIC is better, but ask for advice as to when to fit it when choosing other optionsHence choose carefully.
INJECTORSBigger injectors empty your wallet and add no power unless part of a E85 fuel retune or major engine rebuild. Save your $$ for suspension and get some GOOD improvements.OEM Injectors are big enough unless you do a major engine rebuild.
FUEL PUMPMore than adequate up to 50 kw at the wheels after that a 500 hp pump can be retrofittedEXHAUST(Some traps for people here, unless carefully chosen.)Single scroll turbo engine pipes with split collector to fit wastegate is necessary and will add throttle response and is good value, with the correct complete design. High flow ceramic cat in the downpipe is best.Flex joint is needed as well, with correctly located O2 sensor.Get this wrong and the car will suffer CEL lights, deactivate the Cruise control and cause poor fuel economy.The single rear muffler is not that restirctive and adds no value in just replacing this and should be completed as a part of a whole turbo back exhaust kit.In some cases depending on final tune the muffler can be re used with a complete exhaust, consult MRT for this
AIR INTAKEOther than a intake noise no power here. MRT used to supply and fit ram pod style intakes, but with technology and recent testing and on the later models these were made redundant. The positive intake pressure with the factory intake is best kept in place.A replacement panel filter in the std airbox will save on future servicing but give no power improvement.
ENGINE ANCILLIARIESItems such as aftermarket plug leads, high capacity discharge ignition systems etc all will ad very marginal if any improvement.A GFB alloy pully kit if fitted as a kit or alloy crank pulley will result in snappy throttle response.
TURBOOK if you have big bucks a turbo upgrade will add power, but be careful the OEM turbo is best kept in place as the limit is in the engine NOT the turbo and will give no value unless you plan a big engine upgrade. (meaning if you fit a bigger turbo you cant use its benefits as the engine wont be capable of the extra boost)If you want big grunt and big torque then ok, this is an option here, then you need to plan a engine rebuild.
ENGINE INTERNALLike above if you have a solid budget, then a rebuild will give some great and huge benefits, but a rebuild will cost over $7k and then you need to choose carefully there are many options, but only if you REALLY want to.Best value here first and foremost is Pistons and Rods.
OTHER OPTIONSIs the car serviced correctly? Because often a service by a workshop who really knows subarus will be your best choice for first place for power and reliability.
SUSPENSIONcheck out the performance / suspension section for REAL gains and benefits.If I owned a Sti suby, I would invest some of my budget in brakes and suspension as this is guaranteed BEST VALUE!more here http://mrtperformance.com.au/performance/suspension
FREE CHECKRefer the MRT vehicle service section here and take advantage of our free 78 point check to ensure your car is in top shape!
Mazda Upgrades, click here for more info