im not aware of any data posted that showed conclusive evidence that this makes a noticeable difference, especially since, as you mentioned, the air is going through the turbo. All the data ever posted has shown either no difference or even a slight increase in power due to the increased air...
FYI, you are looking at the wrong website; this is the international MST website.
They do not ship to the US.
If you wish to place an order in the US, you must get it from an authorized US dealer like us.
product link
MST Cold Air Intake System + Turbo Inlet Pipe for Toyota Supra A90 A91 / BMW...
its normal for the downpipe to trigger the check engine light in the first 1200 miles.
ignore the light during that period and if the issues persists, contact active autowerke for a replacement.