how legit is that stuff?

 

Very legitimate. It's probably the most popular and respected additive over on BITOG. Most additives get trashed over there by critics (and by me too). Here's a link to much discussion about oil additives with Auto-Rx mentioned quite often:

http://www.bobistheoilguy.com/forums/ubbth...&Board=5&page=1

All of my vehicles have had an Auto-Rx treatment now, and I've been very pleased so far. It's very important to follow the instructions and change your oil filter at least once during the clean and rinse phases.