[konafocuswrc]

i've used almost every brand i can found..
-royal purple
-lubro moly
-mobil 1
-pennzoil
-valvoline
-redline

and currently using castrol..( i m switching btw valvoline and castrol, because wrc sponsor..lol)

to tell you the truth, you wont' feel any difference..synthetic last longer than regular for sure but still..i didn't feel any difference..
or you may feel some smoothness through rpm but this could be placebo efffect..or that is what synthetic is..

while i was on synthetic for first time, i changed every 5000km and oil came out fresh..so i change it after 10000 miles from now on..