Stupid noob question time! How to rout wires/lines through firewall
 

So, I'm starting to stick on my gauges on (Oil pressure, mechanical boost, MAF to MS from IM) and I'm wondering if there's a pre-drilled hole or something, or if I have to do it myself?

Also, I have an electric oil pressure gauge, just wondering where I should mount my control box. There's no real place to do it in the Miata interior since there's really no flat surfaces that it looks good in. The glovebox?

And, apart from the engine bay to the interior, how do I run lines invisible throughout the car? Do I have to take off the dash or something? I plan on running the boost and oil pressure in my pillar mount and the WBo2 in the left boob vent. How do I run the wires to the back of the boob vent?

Also, just another random question, where can I get a strait pipe with a BOV flange and the hoses around the throttle body? All the ones I can find are bent or funny shapes. Will I just have to make it myself?

I used a dremel tool and made the hole bigger right beside the heater core lines, then i routed most of mine through there to where the radio is, and for the vents you just run the wire through the radio and up in the vent not to hard, the sidemount on the pillars is the only problem i had for routing the wire.

There should be a couple holes in the firewall on the driver's side for cruise control stuff (will be plugged off if you don't have cruise) through which you can fit vac hose and/or a bunch of wires. If you're just dealing with a few thin wires, you could poke a new hole or enlarge the one in an existing rubber boot. Or you could drill a new hole or two, just use grommets so the metal edges don't cut stuff.

And, apart from the engine bay to the interior, how do I run lines invisible throughout the car? Do I have to take off the dash or something? I plan on running the boost and oil pressure in my pillar mount and the WBo2 in the left boob vent. How do I run the wires to the back of the boob vent?
- You don't have to remove the dash, you can remove your glove box and that panel underneath your steering column and run it to your A-pillar.

*edit* Btw, I got an A-pillar mount thing for sale cheap if you want it lol.

Also, just another random question, where can I get a strait pipe with a BOV flange and the hoses around the throttle body? All the ones I can find are bent or funny shapes. Will I just have to make it myself?
- I got mine here BOV

You can get different size vacuum hoses there also, but I recommend going to Autozone and getting some because it might not be the sizes you want online (unless you know the sizes of course).

Look at the bottom of the master cylinder then look right. There is some rubber gasket thing which you can violate.

+1 This is the perfect place to route stuff. If you cut a small X in the gasket thing it'll seal up nicely around wires, hoses or whatever. Use a coat hanger or a similar device to fish the lines through.

There's enough room behind the A-pillar trim to run a bunch of wires & hoses. Figure out where your pillar mount is going to be and cut out a piece of the trim underneath it - a dremel tool is perfect for this. You can then shove aforementioned coat hangar down the hole and it'll come out somewhere in the footwell. I you want to replace an eyeball vent with a gauge, just drill a small hole in the ductwork leading to the vent & run the wires through.