What do you think about Motul?Split is probably between OEM and Motul 5w50 depending on tune and whether you track or not.
good advice here from steve, we used motul before and change after every event..Oil is the lifeblood of the car. I used to change my oil in my R33 before and after a Track day, a bit obsessive some might say, but would rather spend a £100 on oil than £15k on an engine rebuild !
Ask a reputable "tuner" what they recommend, and yes it does matter how you use the car, temperature of the weather outside, if the car is used daily or kept and only used a s Sunday drive, Track use etc. etc. etc.