I've tried Restore Engine Treatment in my 2000 Saturn at 100,000 miles because of increasing oil burning. Within 10k miles of using Restore at every 3,000 mile city-driving oil change, I had to replace the 02 sensor, then the catalytic converter a few thousand miles later. Also, the EGR valve would stick open, throwing SES code. After several cleanings of this $130 electronic-controlled EGR valve, I bit the bullet and went to Autozone and got a one. I have suspicion that if I stayed away from Restore, I would not have had to replace the 02 sensor, cat, and EGR valve within 12 months.
Had I learned beforehand, that the "L" in Restore "with CSL" means it contains LEAD - a natural destroyer of 02 sensors and plugging catalytic converters - I would have just stuck with adding a quart of oil every 750 - 1,000 miles and being grateful it's not blowing blue smoke out the tailpipe yet. I may as well have been running on leaded gasoline.
Restore may be fine for older, pre-emissions/cat vehicles, but certainly bad for newer vehicles sensitive to LEAD.