Ever ask yourself "Can I actually change the plugs on my SVX?".  Well of course you can.  All you need is some VERY basic tools, and a LOT of patience.  Remember, I said a LOT of patience, if you don't believe me, you will soon enough when you go to do yours.

I went with Bosche Platinum +4's.  I have used these in my other vehicles, they work great.  Believe me, they ROCK in the SVX!
 

Getting Ready

The first step is the obvious one.  Ensure you have the proper tools to complete the job.  These are extremely common tools they include:

1. Basic socket set, wrenches and extensions (12mm and a short and long extension will do it)
2. A universal socket joint would be VERY nice, however I did not have one.  It is not required.
3. Long flat blade screwdriver
4. 5/8" spark plug socket
5. Jack / Jack stands (yes you will need them)
6. Some new plugs (obviously)  :)

Removal of the current plugs, and installation of new ones

The very first thing to do is to get some parts out of the way.  As I'm sure you have looked already, you really have VERY little room to do this.  Anything we can get out of the way, is a blessing!  The largest improvements come in the removal of the battery and the air box.  This will allow for easy access of the first two plugs on each side.

Ok now that they are out of the way, you can get down to changing your plugs.  Now first as you probably have noticed, your plugs look different than other vehicles.  This is because on other vehicles there is one master coil that provides charge to the plugs.  On the SVX however there are individual coils for each cylinder.  I'm not exactly sure this is a good thing, however I'm sure they aren't cheap.  So PLEASE be careful with them while you are working.

Now in this picture (see below) you can see the two of the spark plug coils.  The bolts hold each individual coil in place.  They are 12mm bolts.  Start with the first one closest to the front of the car.  This is probably the easiest one of the six, so it will show you how they work.

Loosen the bolt for the coil, and start to unthread the bolt.  However do not take the bolt fully out.  The bolt is a handy dandy tool if used right.  If you take the threads out most of the way (see below) and then pull on the bolt the coil will pop out.  As I said before do NOT force it.  If it doesn't come out right away, take the threads out a little farther and try again.  If you take the entire bolt out and the coil still doesn't release do not give up.  Simply thread the bolt in a few threads, and take you flat screwdriver to the side of the coil and GENTLY pry outward.  The coil will pop out.  I had two that I had to do this on.

Once you have taken the bolt out and gently pulled the coil to the side.  Simply take your 5/8" spark plug socket and remove the plug.  Be VERY careful not to force the plug out as it may break.  Once removed check the condition of the plugs.  You can learn a LOT about how your engine is running by the plugs.  A charcoal dusty type color is about how you would want it.  If there is oil on the plug, or it is VERY black then you probably have an oil leak.  If it is a very white chalk like color, your engine is probably running too hot.  Check the net for some pictures, they can be helpful in diagnosing your engine.

After this point, its time to put in your new plug.  Gap your plug if necessary.  However NEVER gap a platinum plug.  This will damage the plug terminals.  Install the plug by hand, never use a wrench to insert the plug.  You can easily damage the threads on the engine if you do use a wrench.  Once you can not turn it by hand any further, use a wrench to SNUG up the plug.  Not too tight, I don't know the exact torque spec, but you can guess by how tight your's were to start with.

Continue this operation for the other plug on the driver side, then do the three passenger side plugs.  This whole operation to this point took me 20 minutes, the last plug took four times that by itself.  You will quickly learn why, when you actually try to get that last plug out.  The space Subaru has provided is incredibly small.  However with some patience, you can get the job done.

First off you need to raise the driver side of your car.  This will allow for your suspension to hang down.  You are probably thinking "Why in the world do I need to do that??".  Well Subaru may have provided virtually no room in there, however they did provide an access hole.  It is barely big enough to fit an extension through however, so it is still quite tough.

Once the vehicle is suspended look on the inside wall of your driver side wheel well.  There is a small rubber plug filling a 1" round (or so) hole.  Pry this out with the flat blade screwdriver (see below).

Once out you will see there is another plug that is on the inside of the engine bay.  It is easiest to pop this out from the wheel well.  Just poke your screwdriver into the back of it, to remove it.  Now with this done, you will see that you now have direct line of sight to your final ignition coil!  Meander the last bolt out and remove the coil.  This takes a long time, however you can get it done.  If you had a 12mm racket wrench this would MUCH easier.  Once removed its time to get your plug out.  If you take your extensions and poke them through the hole, you can manage to get your socket connected inside the engine bay (your socket with not fit through the hole).  :(  If you can manage this to work, take the plug out as usual.  Finally insert the new one and do the same as before.  Do not expect this to be a short amount of time.  This was EXTREMELY tedious (at least for me) and very difficult to maneuver.
 

Finishing Up

Put everything back together.  Replace the rubber plugs your removed.  Also replace your battery and your air box.  Voila, pat yourself on the back.  I would hate to know what it would cost you to get that done!  :)