Originally Posted by disalvoj

Well if you want to see any good number you will need a FMIC. I still have my stock VF39 in mine, just like esemes. We do not see more HP because of the FMIC but considering our next step this is a must. APS states that the SR 40 is more for the WRX than an STi. Yes you will see a gain with an SR 40, but I truly think that if you do get an SR 40 you will not see the same out come of and SR 40 with a FMIC. Plus it is a major advantage for your temps. With the FMIC you will have a signifigantly lower temp than a TMIC. With a bigger turbo you will be spooling up more are into that ESX and will it be able to cool that air down enough?

If you do go with a bigger turbo then get a FMIC. For example an SR 55 with the ESX TMIC did get dramatically lower results because it was smaller and only 330WHP. Then again I could be wrong. I was told that there was no way my DR 725 FMIC would work with my stock turbo because it was too big but guess what 16000 miles and it still kicks ass.

You don't have to go with the APS FMIC but I personally recommend it.

So lets sum it up your ESX with a SR 40? 320WHP that's my guess...

:disalvoj disclaimer: this is my .02 cents take it how you want.