I have a ways to go until I have my 15k maintenance, but since I want to do pretty much all of it myself (it's not really rocket science) I have to look for some of the parts. Does anyone know where I can find a cabin filter for an '04 Sportback? Also, do I need a particular type of spark plugs?

 

You can get the cabin filter from Mitsu, I don't know that parts stores have them yet. The plugs shouldn't need to be changed at only 15k. My 04 is at 32k and runs fine with the stock plugs- they are supposed to be good for 100k. You just need to check a parts store and decide which plugs you want- the Denso Iridiums are supposed to be pretty good, but at about $14 a piece they had better be

 

It seems more than a little strange to me that the Edmunds.com maintenance schedule specifically for my vehicle asks for the change of the spark plugs and cabin air filter in addition to the other air filter and motor oil at just 15,000 miles. Does this reflect on the quality of the vehicle or why does it require all this at just 15k?

 

It would seem to be a generic maintenance schedule. Many newer vehicles, especially GM have an oil life monitoring system- many places will tell you to change the oil every 3K miles, but the dealer always told me to wait for the light to come on, it detects when the oil begins to break down. My wife can go about 7K miles between oil changes in her Buick SUV. On a similar note, Mitsu has plugs that are supposed to last 100K miles from the factory. It's not likely I will ever leave plugs in for 100K, but according to Mitsu, you can. The cabin air filter will depend on the air quality where you live...a lot of pollen or dust will require more frequent changin of both air and cabin filters. Remember, these are guidelines. Ask Mitsu for the service schedule for your vehicle, it'll be more accurate than Edmunds.com