o2 sensor

I am reading a code 27 sub o2 sensor, they are original at 280,000.
I replaced the motor 2000 miles ago with one from Japan. Ran great, pre engine light,now a little sluggish .
I was thinking of just replacing both sensors before and after the converter.
Any thoughts? Brands? OEM seems to be 125 each not including gaskets from overstock. 54 each for bosch locally. We maybe selling the van .
Also the oil light blinked as the code engine light was blinking, maybe due to front being up on stands though.
thanks Donny

denso aftermarket, or NTK from rock auto.... cheap
stay away from bosch

Thanks , replaced air filter and reset codes , so far running well again . I know these can go out in stages so at least now I know to pass on the OEM ones when these ones really fail .







QUOTE=TheMAN;15647]denso aftermarket, or NTK from rock auto.... cheap
stay away from bosch[/QUOTE]