I haven't, but I did have the dealership do their injector/intake cleaning thing about 12k miles ago. I noticed a difference. I did do the seafoam trick through the brake booster line on my old LS400, and smoked out the neighborhood so bad, someone called the fire department as they thought my garage was on fire! It made a huge difference to the LS. But, honestly though, you're not getting all the benefit of the seafoaming if you don't also clean out the intake and specifically the butterfly opening in the throttle body. That, will produce some great results! Plus, a new set of plugs after the seafoam....and you're glass smooth and got all your power back! After I did all of that to the LS, I could honestly, barely keep it under the speed limit on the highway. I barely had to touch the gas peddle to maintain 80mph. And on those cool, damp mornings back in NC, that baby would freakin' fly off the onramp into traffic!