Looking to possibly put a Dana in my Dart,few questions for those in the know.

You're right. There is a convenience charge associated with Cass (Dr. Diff), but it comes with the knowledge and expertise that he possesses.

I have been searching for a while and found some parts that I could put together, but feel that additional costs are worth the peace of mind that Cass brings to the table. I have never heard a bad word from anyone about him.

Call it rear end insurance if you want.