i've tried the lucas upper cyl lubricant which you pour a bottle of it into your fuel tank.. i tried it twice in a 9 month period.. didnt hear, feel, smell, taste a difference at all... bottle was only like $4.95. i feel it didnt do as it said.
so i went ahead and purchased a bottle of redline SL-1 which is highly regarded on here, im going to try it next fillup.
as for the lucas oil additives.. i tried the heavy duty oil additive with some quaker state high mileage(yea weird combination right) . i didnt feel, hear or nothing of a difference.. it was a rather waste of money and a ton of people i heard from said not to bother using that lucas heavy duty oil additive...