I don't use STP either, though STP doesn't present itself as an "oil stabilizer" the very notion of which is utterly absurd. STP also has ZDDP apparently, not that this is inherently beneficial, but that puts it a step above Lucas. It claims to be a product that increases viscosity and contains AW additives, so I'd consider their marketing a bit less shady than Lucas, but that's about it.
I liken LOS as a product to being more to Motor Honey, which claims to work to reduce or eliminate smoke in your worn-out jalopy. This is achieved via a significant increase in viscosity, just like Lucas, and I expect it has no AW additives, just like Lucas. The difference is that Motor Honey is targeted towards engines already on their last legs while Lucas claims all kinds of miracle nonsense and they recommend putting it in brand new engines, the thought of which makes me shudder. Imagine taking an oil that has gone through the Porsche A40 sequence, blended with very high quality bases and a perfectly crafted additive package and then defiling it with the cheapest base oil out of the distillation tower dosed with a huge load of the cheapest possible VII, a squirt of red dye and some bar lube tackifier for good measure and then honestly thinking that the resultant watered-down concoction is an improvement.
Remember, most people know absolutely nothing about oils and lubricants, telling them what LOS is may not mean a whole heck of a lot and that goes for mechanics and enthusiasts. This site is the exception, not the rule.
Like with Motor Honey, often times these products are used in engines already on their last legs, so there is absolutely no recourse there. When used from new, maybe you reduce the life of the engine by some arbitrary amount. Let's say for the purpose of this discussion you lose 300,000 miles, so it's got significant blowby at 8-10 years and 150,000 miles. At that point you are already well out of warranty, so where's the recourse there? LOS isn't going to cause immediate catastrophic engine failure when added in the concentration advised. It dilutes the additive package, increases viscosity and I expect increases deposit formation, varnish formation, wear...etc. But all of those things would happen slow enough that it would be very hard for Average Joe to be able to pin it on Lucas and he/she would probably blame it on the "junk OEM" saying "that 5.3L GM pile wore out way too soon, started drinking oil at 90K even though I had Lucas in it at every fill! Typical GM garbage, imagine how long it would have lasted if I hadn't looked after it the way I did."
People get invested in the mindset that this stuff "works". It's the easiest with products whose claimed performance is, for the most part, impossible for them to qualify. It becomes propped up by the butt dyno, their hearing and they toss out words like "smooth" and "peppy". Probably the only truly Joe Average qualifiable characteristic is oil consumption and if you are dealing with an engine drinking oil, it has a problem.
So $17 for the Valvoline, but $22 is too much for M1? How much does the LOS cost?
