Since my iffy little 1 liter injection engine of the Hyundai Atoz is used quite well ( i drive quite fast where i can) i use high quality oil, added Teflon to that ( special mix i wrote about here) tuned the engine, and will replace the automatic gear oil this next December.
Topspeed of the little car was 130 KM/H now 155 - 160 Km/h
Tuning added 11 Hp to the 55 Hp it had, but the whole car weighs just 833 kilo's as it stands on the road, or 1800 pounds.
Interflon 25 Teflon is the name, they also have additives for gearboxes.
http://www.kemi.is/mediafolder/pds/FIN_25_3038_PDS.pdf