Dodge Repair: oxygen sensors Down vs. Up, difference?, dodge ram 1500, statistical variance

Question
Hi:
In reference to the Bosch 13100 and the original factory installed oxygen sensor installed on a 1996 Dodge Ram 1500 PU with 5.2L engine.   

What is the physical difference between an upstream and a downstream  OR a  "before" and "after" C.convertor oxygen sensor as far as the physical or technical performance?   Should both sensors be the same brand? Should both sensors be the exact same brand & part #??  What is the statistical variance among using any two 4 wire sensors?  what is the statistical variance using 2  different brands of sensors?  Should they both be the same type as far as titanium or zirconium composition?  When I first rectified the check engine light, I installed a Bosch # 13100  in the downstream position.  Some references label this Bosch sensor as an upstream part #.  This worked as far as the check engine light being off.  I now have a check engine oxygen sensor code Bank 1 sensor = slow response.  Should I unbolt this Bosch & install it in the upstream position & buy a new one for the downstream position?  or  Is the difference between an upstream vs. downstream sensor really not significant?  Is the physical size dimension, diameter,  & threads / inch the same?  I did not find this info on the Internet.  
Thank you,

Answer
u wont find any info like that  because it is irrelevant to anything that u want or need to do.
If the parts places says there are different numbers for different banks and up and down  U will just haft to go with it  as far as the 2 and 4 wire system   get the one that is designed for your truck.