Installing the headunit is easy. Speakers might be harder if they're not the same size as the factory ones in your car right now. This is a write-up for my 2nd Gen Camry.
Installing headunit:
1) Disconnect negative battery terminal.
2)Remove the fascia panel. Because your car is differnt, you're going to have to work out how to remove it yourself. Mine was held in by clips behind it, so it was pretty simple. You MAY or MAY NOT have have screws as well, i don't know. But if has clips only, pull out the ashtray and then pull at an angle upwards to free the bottom and keep working your way up. But do not fully remove the fascia panel from the dash as there is a wire still connected to it.
3) Disconnect the wire, which is for the cigarette lighter. Then move the fascia panel out of the way.
4) Remove the screws retaining the radio bracket to the body. I had rivets on mine as well, so i had to drill them out.
5) Radio should come out now. At the back, disconnect the plugs and antenna. I used a screwdriver to wedge the antenna plug out.
6)Screw out the old radio and fit the new one onto the bracket. If no holes match up, you're going to have to drill one in. Make an accurate guess as to where the hole is and mark with centre punch, then drill. Centre-punching helps keep the drill in the spot. Here's the side i had to drill. I was a bit off, so out came the rotary hand tool a.k.a a Dremel (but that's a brand, and mine's not a Dremel).
7) Now, you can either buy a harness to fit the Toyota plug(in the car) and solder it to the one that came with your Pioneer radio (to plug into radio XD), or buy a harness that fits the Pioneer and then to Toyota. It's quickest and easiest to just get the two harnesses( or one, depends on how it;s made), but will cost more. I had to pay $32 for both harnesses, or i could've paid $15 for just the Toyota and then solder. Your choice.
You can solder the above to the below (cutting off the double-sided side - that was the universal side). It would have been pretty easy as well because the harness had labels on the wires, telling you what was what.
OR
Just buy the two harnesses and connect them up. You might be lucky if you can get one; instead of two. This has a Toyota to the brand's universal plug, then universal to Pioneer.
8) Connect the Pioneer plug to radio, and connect the Toyota plugs and antenna radio. The second plug that i didn't connect was for rear speakers, which i don't have. At this point after it;s all connected, re-connect the negative battery terminal and switch car to ACC or even turn it on to make sure the radio works.
9) Screw radio back in.
10) Reconnect cigarette lighter plug, push fascia panel back in, put the ashtray back in and you're done! The end result:
Hey all, fyi I searched the forums and seemed not to have found a full DIY on stereo changing. 
Why not install a car DVD stereo player with GPS ???
Linear Mode
