Its not much of a "mixture", but it really worked on my car. I have a MY02 Wrx wagon with 128,93X miles. The mods are very close to stock, catless uppipe, sti catback, pnp'd td04- intercooler elbows-throttle body, the rest is suspension stuff. I have been getting piston slap during start up since I got out to california, almost a year ago now. I had switched over to Mobil 1 5w30 before I moved, and had done several oil changes with it. I change my oil earlier than most, probably 2k-2.5k jus because I look for excuses to work on my car. Over the summer I had gone to 10w30 mobil one to cope with the intense heat here in the desert. Anyways, I noticed that the mobil one wasnt providing good start up protection, could hear a rougher start, and had piston slap for 10-20 seconds while the motor warmed up. The cooler the weather got, the worse it got. I tried running pennzoil 10w30, for I'd say...2 weeks, before I got frusterated and started researching a fix, vs taking random advice from "ase certified mechanics" who knew nothing about subaru. I checked around with the shops who build subaru motors here in california, and asked what oil they run in them to prevent piston slap. They all said 10w40 rotella T, or when not available, valvoline 10w40 hi mileage syn blend. The reasons were simple, they both come in gallon jugs, they have compounds that are very good for the rod bearings we have, which arent exactly stellar where longevity is concerned, and it resists sheering very, very well. Then I talked to Martin (dynapar) today, and he recommended using a Lucas oil treatment in conjunction with the oil I was swapping out. I went and got some from the shop, and then when looking at it, realized its the EXACT stuff the motor shops had talked so highly of. Its very thick. Martin used the comment "like honey". I spilled a few drops on my oil fill nozzle, and an hour later it was still fighting gravity. So far the piston slap is nearly gone. From startup, I get 3, maybe 4 taps before it completely subsides, vs the 10-20, sometimes 30 seconds of noise. When I immediately begin driving it after start up, I used to get tapping at lower rpms, (1200-1800). Those are now gone, even with a completely cold block. She feels like a brand new motor, and I blame a lot of this on the horrible spark plugs that I replaced along with the oil. I'm just throwing this info out there. More of a documentary of how foolish money can be spent, when 3 hours worth of sitting on my butt researching is the actual solution.