This is not an easy job. Personally, I would not recommend doing this even if you are pretty handy. It is very tedious and requires contorting your hands into some very confining spaces. I lost half a fingernail and the skin off of 2 knuckles. The back of my hands look like I was digging thru barbed wire. You cannot really wear gloves for the intricate work that is involved. You will need male and female torx bits, universal 1/4" and 3/8" adapters, long 3/8" extensions, a long 3/8" wobble extension, ball ended and regular ended allen keys and sockets in 4mm and 5mm, a 10mm and 5/16" combination end wrenches. SpoolnV8 and 997John did this job without removing the turbos, and so that is how I proceeded. After doing it though, I think it may be easier and faster just to remove the turbos. That being said:

1)jack up rear of car and remove wheels. Remove rear wheel liners. Remove tail lamps. Remove rear bumper.




2)remove intercoolers. Bend up the heat shields out of the way.






3)remove heat shield - the following is for the passenger side plugs. The forward torx bolt can be removed with a 5/16" combo wrench working from underneath





4)coil packs are visible now. Push the rubber boots up to allow the clip to be undone, then you can unbolt the coilpack and remove it. The rear 2 spark plugs can be removed now with long extensions. I used a wobble extension on the spark plug socket.







5)the forward plug looks impossible to get to. To R&R without removing the turbo requires - unbolting and moving the 2 oil lines and 2 coolant lines to the turbo. Push these out of the way best you can. You now have to unbolt the 3x 5mm allen bolts holding the VTG controller from the turbo. You can pop-off the actuator arm to ease it some, but this part really sucks. The task requires some real contortion. Try to break the bolts first with a 5mm allen key socket or allen key, then go to the ball ended key. If you can do this, you can probably jerk-off a hamster blindfolded. Loosen the compressor inlet duct to help remove the VTG unit, then you can get to the coilpack and spark plug. Whew!


take a break:






6)the driver's side is no less difficult. The rear plug is relatively easy. The middle one requires the removal of the cooling lines to the turbo and the VTG unit - again, a task only for the "Hamster Whisperer"








7)the forward plug is pretty tricky too. You have to remove the diverter valve then loosen the compressor inlet duct. Removing the diverter give you just enough room to wriggle the coil pack out and to change the plug.




My car has 16k miles on it, and I had the car pumped to stage 2 at 2k miles and 700 kit at 8k miles. I hadn't noticed any issues with the car until recently. I had not driven it more than once a week, and noticed a slight surging of the throttle when going from 1st to second under very light throttle. The car seemed to want to buck and I just figured I was not being deft enough on the clutch. After a long drive up to Dallas though the car started to stumble lightly at around 3-4k rpm under mild throttle. It was a very slight hesitation and I thought that I might have gotten some bad fuel. Mixing with 104 octane seemed to help but did not eliminate the problem. Running a bottle of Techron also just about eliminated it, but I still knew something was off. I did not get any CEL for misfire nor did any codes pop up on the scantool. The issue was mild enough that I probably could not reproduce it for a service tech.

Reading up on the 996tt boards the symptoms seemed to match what others had noticed. Sharky's post on 6speed made me start to wonder if the plugs could be the issue. So, I decided to plunge into the job. I originally was going to go back with the stock Beru/Bosch plugs, but the dealership and local wholesalers did not have them in stock. This pushed me to doing the Denso double platinums in 1 stage colder than stock. These are the PK20PR-P8 plugs which wholesale at less than $6 per plug. Looking at the tips, you notice that the insulator is shorter than stock, and the electrode is a fine tip similar to stock. My old plugs were showing some wear, with about 8mm gap in the plugs. Stock recommendation is about 7mm so there was definitely compromise there.






Happily after this tedious task, the car is running noticeably smoother than before. There is no more surging or hesitation, and my butt dyno thinks the car found a good 20-30hp. I hope that the Densos last another 15k miles or so, because this job made me feel like this guy:

 

great write-up but I can not see the pics

 

Great info.

After seeing the pics and thinking about it this is a no brainer.

I d pay the dealer $600 gladly!!

Cab

 

I was going to offer you a beer, one just didn't see like enough...so here:

 

Excellent posting, again. We truly appreciate the time and effort a blow by blow DIY takes. I'll likely do this work to my '07 when I put the AWE exhaust in, as I'll need to take down the bumper anyway. Used to the skinned knuckles from doing 951 header swaps! Ugly and painful!

 

After looking at the pictures again, I know what to get you for Christmas:

new gloves LOL!!!!

 

Yeah, I'm that cheap!

 

Well done man I know it's a horrid job it makes you wonder of they ever considered that plugs actually need to be changed! the denso is a good plug although they don't seem to last as long as the Bosch.

 

Crap. That's impressive. I just don't have that kind of motivation

 

Wow...this continues to reinforce my belief to have a certified mechanic do this type of work. I eny you having the skill and patience to undertake the DIY stuff.

 

Thanks for a great write up. That is one job I am not looking forward to and may just farm out to the dealer.

 

Great report! I see now why the dealer charges soo much.

Why did you change the plugs? Was it because of mileage or the mods you've done? My car has around 600HP but only has 5k miles. when should I expect to change my plugs?

 

https://www.6speedonline.com/forums/...97-turbos.html

 

This is the one DIY job that I bailed on 1/2 way thru and just let the dealer have at it. They drop the engine and bang it out in short order. I dropped mine off at 8AM, it was done and washed at noon.

 

Yup I have to change the plugs in my 08 Imprezza still. Along with that frigen trans fluid I can't find anywhere. Don't know it is absolutely true we have to use the special stuff or can use the standard off the shelf stuff?