I used some of that Restore on my old Mustang that was burning oil bad on 1 cylinder (kept fouling the plug). It seemed to help a little but I think any of those products are really just snake-oil. I have found STP to do a good job of quieting a lifter that leaks down on the 300CE. Without it it will tap for a few seconds on cold startup , the STP seems to stop it.
As far as tranny additives go most of them are seal softening types . If you used some , put it in 1000 miles before you change filter and fluid . I don't think it's a good idea to leave it in between changes.

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