Engine oil Castrol or Shell

Either Mobil 1 or Castrol GTX - never had oil issues with either one.

Running the OE Castrol 0w-20, pushing the car very hard up a twisty road in NC/SC, I saw a maximum of 235F with an ambient temp of 75F. My averages with normal driving are close to yours. These temps are well within the oil's capability.

Rotella T6 is a great oil for these cars, and it's what I use.

i been using it religiously for now 85k miles, i have tried Quartz Ineo 5W30 502 Spec oils made my engine produce more heat and valvetrain noises. The Castrol Edge 0W40 I use now tops out at 212, normally sitting between 205 and 210. With the 5W30 Quartz it was constantly sitting at 227-237 which is pretty significant.

this oil is my most trusted, been using it since new with the best results ( i tried Mobil1 0W40 and a 5W30 Total Quartz once each and oil temps were 15-20 degrees hotter in similar ambient temps and conditions with both of those so i decided not to use them again).

They also have the 5qts of Castrol Edge 5w-40 for under $30. I've been running that in my cars since 2005.

Last change I did was with Castrol Edge 0w-20 no issues.

If I feel like spending money I\u2019ll buy Redline or Motul, they\u2019re Group 5. If I wanna be cheap and still want really good oil I\u2019ll buy Rotella T6.

I've always run conventional Castrol 20/50 in my Gti's (past and current Turbo) without issue.

Rotella T5 15W40 seems to be on sale somewhere at all times for an absurdly low price + a filter. Ive been using that in my JH block with G60 topside.