Are there any downsides to FMICs? There have not been significant amounts of problems with FMICs. Care should be taken by the end users to ensure through the Vendor that any special fitment requirements are discussed and understood prior to purchasing. Even “bolt on” intercoolers maybe have slight issues that you need to be aware of prior to purchasing. STi owners need to specifically ask about fitment as the majority of FMICs on the market were designed for the WRX. Other things to talk over with your Vendor prior to purchasing:
1. Will this FMIC come with a replacement bumper beam or will it require modifying the stock unit?
2. Will this FMIC require any modification to the bumper skin?
3. BOV use. Can this FMIC use the stock unit or accommodate an aftermarket BOV made by XXX? Some FMICs have issues with certain BOVs so it is better to determine what manufacturer/type of BOV you need prior to purchasing your FMIC to ensure a proper fit.
4. Intake use. Can this FMIC accommodate an aftermarket intake by XXX? Some FMICs have issues with certain intakes so it is better to determine what manufacturer/type of intake you need prior to purchasing your FMIC to ensure a proper fit.
5. Can I still use the stock foglights?
6. Does this FMIC have any issues with the placement of any underhood components such as the battery, coolant reservoir, etc.?
7. Can I use this FMIC on a wagon?
8. I have a 2006….will this fit?

What are the hidden costs with FMICs? When switching to a larger FMIC, you will face the additional expense of an aftermarket intake. You may also have to use a specific type of BOV.

What about the additional lag of a FMIC? This topic is highly debated. The two general trains of thought are:
1. FMICs increase turbo lag.
2. FMICs decrease throttle response.
Though there is much debate as to which one is actually correct, many believe that lack of heat soak issues of a TMIC are enough benefit to overcome the associated lower RPM issues of the FMIC.