Engine radiator Koyo or OEM BMW

Had a Koyo on mine, it was perfect and kept the car cool year round in Southern California even in the canyons on 100+ degree days. It also handled track days without a hiccup

I have a Koyo on my car and have no complains. I do tracks days and have never had any overheating issues.

Koyo is what I'm using. Quality stuff. I'd highly recommend.

I had an older BMW myself (E36) and if you want reliability you'll need aftermarket (improved) radiator, radiator hoses and water pump.

plastic radiator ends tend to crack and leak on the 4.4's. make sure you get an aluminum upgrade.