The cabin air filter retro is a good idea but it probably won't help extend the life much of your allready 12 year old evap unit. It will help the new one when yours is replaced but is the car going to be around another 12 years?? The filter mount is relatively cheap only around $15 but the filter can be as much as $25-30. I took the mount to the auto parts store and with a little trimming was able to geat a $6 AC/Fram filter to fit. Think it was a 3019/3009 or something like that. It won't have activated charcoal though but if you're always in the "recirc" mode it wouldn't make any difference. You may get a little rubber smell for a while after all the engine doesn't really care what the air smells like.