I was thinking about buying one of these for my '05 STi. Anyone think it helps?

Probably not and if it does you can't tell the difference. It's mostly just for bling than anything else.

make your own

At one time I had a Zerosports replica shroud that consisted of a CNC-cut stainless steel plate that fits over the radiator support and covers the gap between the support and the radiator itself. While it did prevent air from escaping instead of going through the radiator core, it was sufficiently thick to almost require adjustment of the hood latch mechanism. It also weighed a couple of pounds. You can probably fabricate something using closed cell foam insulation or door jamb insulation from a home supply. Just fill that gap around the radiator so that air doesn't take the path of least resistance.

Or just get a shroud. They always look nice. :)

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0==WW==0
"…axles of evil…" - george w. bush

radiator shrouds are more for bling factor

yeah well I love my arc radiator shroud...major bling*

^^^baller

^^^baller
naw your the baller with the prodrive rims and prodrive lip!

ive read at nasioc that it lowers temp to 5 degress!!