Help with Tech Codes for 1997 Boxster
 

I recently "inhereted a 1997 Boxster and a project car.

I am getting the following Techs Codes.

P1117 O2 sensor heater behind cat, bank1

P1121 O2 sensor heater behind cat, bank 2

P0160 O2 sensor CYL 4-6 behind cat

P0153 O2 sensor CYL 4-6 ageing, ahead of cat........

Does this mean I need to replace all the O2 Sensors.

I am a newbie and really need help......