I want to buy an auto meter boost gauge for my 07 wrx. My question is, should I get an electronic or a mechanical one. I know the mechanical one has a vaccum line...but can it be connected to the line that goes to the bov or does it have to be somewhere else?

Either type will work fine. Both require a vacuum connection, the mechanical gauge gets the hose connected directly to the gauge itself, while the electrical gauge has a remote sensor to which the hose is attached and from there a wire connection goes inside to the gauge. For both the proper vacuum tap point is the bypass valve hose.

Thx. But where should I wire the gauge lights to?

Subscribing - I also need to know where to splice the gauge light so that it dims along with the gauge cluster. Are our WRXs "pre-wired for the column boost gauge and, if so, where did the hid the wire? Thanks

Radio system harness, dimmer wire...its either violet or orange/white. I think.

if you remove the stock stereo, there's an empty harness/plug in the rear. this is where the oem boost gauge connects to.