I love my blue WRX wagon. It has a little over 25K miles and not a single problem. The only mods so far are a fumto oil drain valve and some Hella super twin horns.
I normally change my own oil and filter - Mobil-1 10/30 and OEM filter. However, one Friday, I was getting ready to go on a trip and I dropped into the local dealer to have it done. I told the service manager that I had brought my own oil and that I had installed an oil drain valve.
They took my WRX right in to the service bay, jacked it up, and then while I was watching, the service mechanic starts trying to find a wrench to take the fumto valve off with. I had to yell across the service department for him to stop, and show him how to use the valve. Then, a few minutes later, I had to stop the mechanic again from putting the shop oil in.
Right now, I don't trust that service department to do anything right. I wrote and told the manager, but have heard nothing back. The next closest dealer is about 50 miles away, but I may have to go that route anyway.