Engine oil Mobil or Eneos

Stick with 5W50. Brand doesn’t matter as long as it’s a quality supplier. I used Mobil 1 in the beginning

Always used M1 on my 30 year old Celica/camry. They both run flawlessly. Done over 30 changes on the Celica (160k miles)

Been using Eneos & changing it every 4k miles/4 months. Congrats on the WRX

Mobil 1 has never failed me over 3 Wrx’s and 1 Brz and an old forester

There is no “break-in oil” just ENEOS brand 0W-20. KIA and ENEOS have a partnership and the factory oil fill is this oil

I’ve only used this Mobil1 oil for my 21 Camry SE. I do 5k intervals and it’s been great for the past 60K.

I run 0W-40 Mobil 1 European that meets the spec on the bottle. 10k changes since new.

Ive owned four 5.7s starting in 2005.

Changed all of them with 5w20 full synthetic, no real allegiance to a brand, but always a major brand (Mobil1, Valvoline, etc); typically 5k - 7k miles  between changes .

2005 had 250k , burned no oil, died when it hit a tree

2006 had 240k, would use 1/2 qt over 5k miles after about 225k.

2013, traded in with 225k, burned no oil.

None of these ever had a valve cover off.  I purchased the 06 and 13 new.  The 2005 I purchased with 100k on it.

The 4th is a 2021 with 35k on it. So far, so good.

She burns ~ 1 Quart/5000 Miles.

BTW, Mobil runs hotter in my car.