o2 placement narrow and wide
 

just picked up a used greddy kit, came with a RM 2.5 down pipe with a o2 bung right at the turbo outlet

was wondering if i should move the narrow and wideband sensors back towards the cat?

what about a sensor behind the cat? no? i dont think that will work.........

The OEM O2 sensor seems to last OK in that "on top" position, but for some reason my NTK 4 wire did not do so well there.

Your WBO2 should be on top of the pipe in that open area by the transmission before the cat. If you are going to weld in a bung for the WBO2, put another bung about 12" from the turbo for a 4 wire narrowband just in case you want to change later.