We get lots of calls for upgrades on this model, as this car is becomming even more affordable, 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 big change for its MY02 / 05 2 litre base model, it has good value potential and is a high performance car effectively detuned when compared to the STi model of the same year and later!There are some great features of this car, 4wd, turbo 2.0 litre and most of all, a sensible budget with some well planned upgrades and it turns a great car into a STi beater!(Editor note, this model is a detuned option, with sorry, to say very fragile pistons if poorly modified, but some simple mods makes this a great model, much better than the later model at a much lower cost)
ECUCan be converted and fully tuned, using EcuteK Software for almost any improvement, ECU allows solid 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
ENGINE WEAKNESS'sBottom end and mid range performance can be dramatically improved with ECU tune. The engine is very detuned (as subaru dont want it to beat the STi ) and also limited due to emisions requirements when delivered by the factory.Poorly designed upgrades magnifies the risk of piston failure. 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 should be run on 98 Ron Fuel unless a custom (ecuteK) map is done.The turbo is but if over boosted with boost controllers etc will result in costly turbo failures.
ENGINE SENSORSOn this model the aif flow meter sensor is more reliable than MY99 / 00 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 incorrectly 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.
INTERCEPTOR ECU OPTIONNot worth considering as the intercptors simply do not have enough options to tune and modify the latest technoplogy control inputs.ZERO VALUE
ECUFactory ECU retune is best value. See notes above
INTERCOOLERFactory fitted unit is "very average", dont fit a FRONT mount unless you plan a mosnter engine with resulting turbo to suit.Use a better replacement MRT top mount, but choose carefully.
INJECTORSBigger injectors empty your wallet and add no power unless part of a E85 fuel retune and are simply not needed unless you do a full engine rebuild.
FUEL PUMPNeeds to be replaced with any mods that inlcude a turbo, such as MRT;'s "XC power kit".
EXHAUST(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.On hatch models the single rear muffler is not that restrictive and on the and adds no value in just replacing this and should be completed as a part of a whole turbo back exhaust kit.Consult MRT for this.
AIR INTAKEOther than a intake noise no power here. MRT used to supply and fit Cold air intake and 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 will fit some models, this model has a three part kit available.If fitted a kit or alloy crank pulley will result in snappy throttle response.
TURBOIf you have the budget a turbo upgrade will add power, (such as a MRT XC kit) , but be careful the OEM turbo is best kept in place unless you have the right other parts to match a new turbo upgrade.As the limit becomes close to the engine depending on your choice turbo and will give no value unless you plan carefully. (meaning if you fit a bigger turbo you can use its benefits but be careful as the extra boost will need to be tuned carefully )
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 new HD 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 this WRX suby, I would invest first in the MRT XB kit as it will then have more power than the later 2009 model, and then 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