Nice gauge, can't go wrong with Innovate. For oil temp, rear galley under the TMIC will give you accurate readings. Though it has been said that in the oil pan is ideal. For oil pressure, front galley under the alternator. Sandwich plates offer ease of installation, but reports of occasional leaking are not uncommon. Personally, I have mine installed in the galley locations mentioned.
Keep in mind that if go with the galley locations, you will need a plug adapter like this (assuming 1/8NPT threads):
http://prosportgauges.com/subaru-oil-galley-plug.aspx
Good luck.