Anyone been refused warranty work due to a modification???

[Lambeau]

Last week I had my 06 X at the dealer for warranty work to address the xenons for the third time, passenger door unlock for the third time and a service engine soon light. I've had a cold air intake on my X for at least 30,000 miles and apparently the mass air flow sensor is faulty but they won't service it because I have a cold air intake. They want to charge me $528.00 for a new MAFS. I asked the service person if Dinon (sp?) offers a cold air intake and if they would have serviced it if they installed that. She didn't know what to say. I also asked her how the intake could affect the MAFS and she also didn't know how to respond. So, for now I have not replaced it. What do you feel are my options? Should I put the original intake box back on and go to a different dealer for service maybe?