Originally Posted by Aether_Snap_STi
wow, how much lag would you see with a stock turbo and that much extra IC piping??
Id stick with the TMIC.
If the core is efficient there will not be very much lag going to an FMIC kit. If you care to work out the air consumption of the engine at a particular RPM and compare the volume of air in the OE top mount set up compared with that volume in the front mount set up you will see that although there is an increased volume of air, the increase is very small in relation to the engine air consumption per second.
The biggest cause of lag on a front mount set up is either a poor core, poor mapping or no mapping at all.
Generally by 350 bhp fly on a WRX New Age the ACTs are such that it is worthwhile moving to an efficient FMIC. On an STi producing 392 bhp (STi TMIC) I picked up 9 bhp fitting a Hybrid FMIC straight out the box and a further 9 bhp from mapping so even on the more efficient STi 8 TMIC there is a good power gain moving to an efficient front mount once you reach the right power level.