I go to a nissan dealer where I live and they are great to work with. You just have to find the good people, I had my N/A in john elway dealer several times for rough idle and they finally found that my injectors were bad. Never fixed because of the cost, then I went to boulder nissan they are great, I pull in the garage and the one guy says sounds like you have a bad injector. Go figure some people just know stuff. They were also willing to do a turbo Jspec swap for me.