So, keeping an eye on a P0420 code that I'm thinking/hoping is just an O2 sensor. (I've gone thru this before in old Toyotas and usually turns out to be upstream O2 sensor). BUT...........I don't feel 100% confident on *which* sensor it should be.

I'd like to stick with Denso and thought I had it figured out with the 234-4620 but that is or the FA23A1 (non-ULEV) motor so it's not that one. (I have FA23A4) I *BELIEVE* it's 234-9014. But it is...........DAYUM EXPENSIVE!!

Sooooo.......any options (I know there's Denso then there's everything else) or alternative suggestions welcome...(Bosch maybe?)...unless I'm wrong on the part # and then I need more help than that anyway.

TIA