Having a custom manifold done through a GB on this board..Should I have him tap it for the GReddy EGT sensor and the O2 sensor? If so, where is the best place to put them....If not, where should these sensors be mounted? Is there anything else other than the wastegate flange that I should have him do now? I could use any suggestions you guys might have..

 

i would do the standard setup: EGT tap on runner #3 (2nd from left when looking at engine)

o2 sensor is typically mounted near the cat, at the end of the downpipe. not before the turbo in the manifold.