Sensors, to replace or not to replace...

alright, i bought my wagon from Westside VW back in December, brought it in and made them replace the downstream O2 sensor, and they "cleaned" the other... well... its throwing codes and the other day we had the exhaust off and saw that the one they replaced the one they were supposed to, but the other one they "cleaned" is SHOT. so, i guess my question is should i just go ahead and replace both while i am at it, and the Knock sensors too, or just the one bad sensor thats basically an open element? i am pretty poor at this point and no longer have access to a lift with a lowered car. thanks for your input.
Chris

 

knock sensor if you are getting the code will make the car slow as dirt and run like poop

 

its throwing a knock code and the O2 sensor code, i assume its why the car bogs down sometimes now. lol

 

for sure

 

now... the next goal is to find a subi dealer down here in Mankato or a place where i can get on a lift...

 

clements in rochester

 

i suppose i will have to head over that way

 

My roommate is in charge of the shop on campus sometimes. We could prob get it on the lift sometime.

 

dude that would be awesome, btw, sorry about that hardware i borrowed from you, its in my center holder thing