Hey, i just installed subs in a friend of mine's car. He has a 95 318i so i assume the layout is pretty much the same. I assume you your battery in located in the trunk which makes life so much easier. You should have wires for +,- (ground), RCA cables, and a blue ant/power cable. The positive cable attaches directly to the positive terminal of the battery. It should have a spot to screw or bolt on. Make sure all fuses are out while connecting the wires. Then the ground cable could attach directly to the battery i assume, but I am not sure so we attached it to a randon bolt we found behind the tail light panel after checking to see if it was grounded. Most of the exposed metal anywhere in the car is grounded. So now you have you power for the amplifier. Then you must run the RCA and ant/power cables from the head unit to the trunk. The RCA cables send the data and the ant/power wire tells the amp to turn on when the car is on. First pull out the head unit and put it somewhere safe. Next we found that the panel that displays time, temperature, gas mileage, and all that good stuff just pops out with a little force. Once that is out there is a big hole and the cables should be able to run from the hole where head unit goes down into the new hole. That's the easy part. Next unscrew and remove the plastic console part that is between the seats that contains the emergecy brake and cup holders. That should be able to totally be removed. So you must get the RCA cable and ant/power cable from the display panel compartment down to the spot where you removed the console. We used a stiff wire and stuck it right through, taped the cables through it, then pulled it back through. Now you have to pull the back seat cushion out. It should just pop out if you pull on it. You need to get the cables under the carpet to the under where the back seat will be so they will not be seen. The carpet should lift up and the wires can be pulled through fairly easily. Now you need to get the wires into the trunk. There are usually a bunch of wires already running from the rear seat to the back of the car. Just follow one of those paths and pull the wires through, it can take a while to find a good location. Now in the trunk you should have the RCA cable, the ant/power cable, a positive wire and a ground wire. These all plug into the amp, it should be labeled. Then in the front reattach and put everything back together. The ant/power cable which is usually blue needs to be soldered to the blue wire coming out of the head unit and the RCA cables just plug in. Make sure you know which channel (left or right) the cables are plugged into because they need to be the same on the amp, i dont know if this matters much with subs because they are non-directional. The rear seat can also go back in and your car should be back to normal. Attach all the wires to the amp and hook it up to the subs, i assume you know how to do that if not post again, then put the fuse back in, start up your car, and cross your fingers. It should take no more than 4 hours if everything goes smoothly. If you have any problems give me a holler.