I did a total fluid change a few weeks ago and while at Autozone I picked up a bottle of the Lucas product that they seemed to be promotiing. I currently have no problems but at the time it seemed it may be a good idea to run a product like this every so often. I have never added it though since I have Questions.....
1. Should these type of products be used period?
2. If so how often?
3. Is there any product (brand) proven to work or work better than any other product?
If there are no negatives, I'll probably use one of these producs with every oil change. Recommended or not?

 

I used them in my old car. I used Redline Fuel System Treatment. I have not used them in my S. I would like to know also what people are using.