Engine oil RED LINE or Motorex

Red Line.

I like red line oils, because they have a bit more zddp which is nice for the rockers.

At the end of the day, pretty much anything in spec will work fine.

That being said, I did a bunch of research for my V85 and determined that Motorex Cross-Power does the best in high demand applications. Air cooled engines can have a really wide temp range. That's what I use.

On chilly winter mornings (SF Bay Area) the car did not like reverse or first gears. Subsequently switched to Red Line engine oil. More power, better mileage.

Ran Redline 5w40 when it became purely a summer car in ~2013. ... Not seals are leaking, no issues of any form. Car has been Cobb stage 2 91oct tuned (OTS, not pro-tuned) almost 14 years, with a Crawford v2 AOS, Killer B oil pickup + windage tray being the only reliability mods, and it doesn't burn a single molecule of oil.

Redline is great, used it for years in a track car.

My STI also used it for a while (0w40), but then switched to Rotella.

Redline user have been since I picked up my 04 WRX wagon two years ago. Auto crossed and rally crossed. Works great have had zero issues, also at 170,000 miles on the original engine and still running strong.

I use Redline, similar quality and price to Amsoil, without the MLM BS.

I just put Redline 5w-30 into my 2011 STI at the last oil change. We'll see how it goes.

Engine was noisier with the mix vs. the previously used redline 5w40. Iron levels are up at 6.3 ppm/1000 miles Oil usage increased by 1/2 quart over the redline 5w40 TBN/TAN levels are worse than 5w40 at comparable mileage