i have changed the standard manifold on my mates rb20e to a set of coby headers,,does it matter where the lamba sensor goes as there is no hole for it.the header is 6 into 2 into 1,the only space available to put the lamba sensor in is on one of the 2 downpipes ,will this be ok or will it give false readings as only half the exhaust gases will flow past it,should i extend the wiring and put in in the single pipe which is underneath the car,any help would be gratefully appreciated