Here's the text of the letter referred to above:
Thank you for visiting the Subaru Web site again. I hope that you have been enjoying your WRX!!
First and foremost, get that nasty word VOID out of your vocabulary. The ONLY way your warranty from Subaru will be VOIDED is if you take it out of the country.
Now, for the facts. We do not recommend the installation of any aftermarket parts in any of our vehicles. Doing so, will NOT affect your warranty. But, any problems caused would not be covered by your warranty from Subaru.
For example, an air freshener is an aftermarket product. Therefore, we would not recommend that you install one in your WRX. But, it is really not going to cause any problems, so there would be no harm or problems caused.
Finally, this is your WRX. Therefore, you can do as you deem appropriate. But, if the installation of an aftermarket part causes a problem, you would be responsible for paying for the repairs.
If you need further assistance, please feel free to contact us again. Have a great weekend!!
John J. Mergen
Subaru of America, Inc.