Tapping for Sub Amp, can I tap this?

[jining]

Anyone know if this is an ok spot to drill/tap a ground for a sub amp? I can't find anywhere exposed besides this area (this is not my car in the pic) and I'm not trying to rip apart the panels if possible:

[Aok303]

isint that where the tubing for the Gas is?

if this is an avant just do it in the spare tire wheel area and you can snake the line up the side with out pulling panels or anything. and you can get under and spray it with rubber compound or a primer so the hole and screw tip wont rust.