I know it's been a while since you're initial post, but since I just went through the same thing, I figured I'd throw in my 2 cents. I have a friend who is a Nissan mechanic, and has a really good machine for cleaning the injectors. I was at his shop yesterday working on some other things, so I went ahead and hooked it up and let it run for about an hour. My vehicle has 75k miles, and I was shocked at how much crap got blown out of the exhaust. The system hooks into the fuel in and out on the injector rails, and your x will run off the machine instead of its own gas tank for about 30-45 minutes. The machine will have some high octane fuel mixed with other potent chemicals designed for cleaning injectors. My X ran like new again after the service, and I would definitely recommend it if you have the money(coming from someone that got it for cost: $25 in chemicals). This is the same thing that the dealer is quoting you for, and that is approximately the going rate for the injector flush. You can find it as low as $75, but I don't really know if they will do as good of a job, or let the machine run as long as the dealer would. Anyway, just thought I'd let you know that the cleanout does work.