Those cars aren't too hard. It does seem at first that you're going to have a lot of trouble with the dash, but it doesn't really get in the way much at all.
Well, unless you're trying to do a super-stealth install and hid everything....then it would get trickier, I would think.
Anyway.....
Take off the lower half of the steering column shroud, the driver's kick panel, and the driver's door sill. Optional---pop out the change pocket on the left of the driver's dash. It's easy and lets a little more light get into the underdash area.
Prep your brain so that all of your ignition wires are together, and so that they're long enough to reach from where you intend to put the brain, to the wires that plug into the ignition switch. I usually zip-tie the brain high up above the driver's kick panel.
Then you can just pretty much let the brain sit right on the floor of the car, run your (already prepped and bundled together) ignition wires up there, connect them......after you're done, zip-tie them along the steering column wiring harness.
Other stuff I can randomly think of:
---TEST the ignition wires (of course!), then make notes so you know which is which, and then if you unplug the igniton harness you can stretch it out straight, cut into the factory tape a little bit, and then you'll have enough room there to make your connections.
---The trim around the instrument cluster pops off, then one screw at the top of the cluster, then two "hooks" that hold the bottom of the cluster in. Sounds hard but you'll see it's easy when you go to do it. Lower your tilt steering all the way down, lay the cluster down sideways so you can see where the wires go in.......tach is a black wire....I want to say it's the black that's right next to a RED / white....it's been a while.
---The trunk-release switch, you can reach in from behind where you removed the change pocket, and push the switch out.
---When you go to find the doorlock wires in the kick panel, just take a close look at everything in that area before you start, and you can clearly see that a bundle of wires comes in from the driver's door and goes to two plugs. The lock wires are in one of the plugs.......green and blue / YELLOW? Something like that. They test while turning the key back and forth in the exterior key cylinder of the driver's door.
---Along the doorsill there's a harness running to the rear of the car. Green positive parking lights, GREEN / WHITE brake, and RED / yellow door trigger. There are two GREEN / WHITEs; test carefully. The RED / yellow catches all five doors, including the rear hatch.
---If you have to run wires under the hood, there's a big factory grommet above the gas pedal. If you look at the other side under the hood, you'll see what looks like a "nipple" off to the side. Cut the tip of the nipple off, and you can pass a coat hanger or old car antenna through there to fish wires through. Under the driver's dash, the steering linkage is totally exposed.......wiggle the steering wheel and make yourself aware of the linkage, so you'll be able to run your wires across without danger of them getting caught up.