So I returned the DTT kit and bought the Thundermax auto tune kit after speaking with them for over an hour. I get the kit and the new O2 sensor on the front header will not fit because it is too long and is striking the oil filter housing. I cannot believe all the problems I am having with these new Rineharts. I am seriously considering pulling them off and sending them back !! 
So the location or angled orientation of the bung is the problem?
C.O., I never made an opportunity to compare the physical size of the sensors we got with the Thundermax kits against the stock parts. If there is a significant difference I guess that could excuse the pipe maker. After all, they're building to replace stock parts, not aftermarket.
Having said that, most o2 sensors I've had in hand were close to the same physically. Not a significant amount of difference. With the sensors that are supplied with the T-max package you can have plenty of room. Granted, I put my bungs on with the sensors in hand in pre-existing pipes. So I could pick what seemed the ideal location. But it's really not rocket science making these things fit in there. Here's where mine went: