So I recently had my engine replaced and I noticed I have bosch spark plug wires now I know I had a bosch o2 sensor n that was crap. So I'm thinking about replacing the word n plugs. Out should I leave them be?

 

If you have a misfire, suspect them first. Otherwise if they are working, no need to waste the money right now.

 

I've actually used Bosch wires on a lot of cars (they are better then the cheapest wires at the store).
I have never had a problem with Bosch wires and they are also lifetime warranty which is great.

But Bosch plugs and o2 sensors have been known to be problem points.