I need to replace an O2 sensor and the choices are:

OEM Lexus - $140
Denso - $83 (my understanding is that these are the OEM)
Germban -$36
Automotive Leader - $30

Now during research here I saw a post about aftermarket ones not working well. But all these non-OEM sensors are rated 4.5 stars with many reviews and have a warranty. Is there really much reason to not get the less expensive one?

 

One of the O2 sensors went out on my 2002 GS300. The dealer wanted $156 for an OEM one. RockAuto had a Denso for $50. It was the exact same Desno part as the Lexus OEM one, right down to the Denso box and Denso part number.

 

I forgot to say I'm currently in the Philippines rn and it will be for a while, nevertheless, i found a denso camshaft sensor (90919-05060) but it says that it is for a corolla altis. Hence my question, is it possible to use the same part for my es350 considering the fact that it has same parts num?

 

Same parts number is the same parts number, Toyota and Lexus have overlapping parts for many vehicles due to common design/engine. For instance, Camry and ES series in the United States although too different brands and designs on outside of vehicle, under the hood, they share many components. I generally stick to Denso and OEM parts for the oxygen and air/fuel sensors.