Engine oil IDEMITSU or OEM BMW

Idemitsu to both, because it’s designed and tested on rotaries.

I use idemitsu rotary 20w50

I stick to Idemitsu. I have a Sohn adapter fitted, so it's 10-30 Idemitsu in the engine, twice a year and Idemitsu Premix in the Sohn adapter and in the fuel tank.

BMW used to recommend you changing oil basically every time you blink, back when consumers paid for 100% of all maintenance. But in order to be more competitive, they began offering 3 year included free maintenance on all new vehicles.

I don’t use the Mazda-branded version, but Idemitsu is my go-to oil in all of our Mazdas

Idemitsu is the only premix and engine oil I’ll use ... you can order it for a good price from TREx performance out of NJ and he will ship

The oil was Idemitsu Synthetic 0W-20 with 12.5k miles on it. Once again, trace metals and flashpoint were within normal range. I also ordered a TBN to measure the amount of additive left and that showed there was still plenty of active additive remaining.

In terms of oiling, get a sohn adapter so your apex seals aren't being lubricated with crankcase oil, and instead are injected with rotary-specific oil, like idemitsu.

Subaru OEM oil is Idemitsu 0W-20. I currently use Idemitsu Zepro\* 0W-20, a high-moly formulation from the same manufacturer.

That's the wrong oil. You want the Idemitsu eco gold medalist advanced moly 0w-20, which is basically the same as Mazda oil(Idemitsu makes the mazda oil).