From most DSM web sites, and comments from tuners like Buschur and another (that I can't remember now, which ditributes Mine's products), say the Evo has a very good flowing O2 housing.
Everybody going through these O2 eliminator DP problems or paying $500 for a Mine's O2 housing, etc.., is, in my opinion, wasting time and money.
The gains are slight if any.
If anybody is truely concerned, why not just do some slight porting on the stock unit?
The only gains above this require either an external wastegate (removing stock one and blocking flapper area at the DP flange), or an O2 housing that seperates the waste gas from main flow and;
1) vents to atmosphere
2) runs a seperate exhaust pipe and muffler for waste gas, or
3) run a seperate pipe down the exhaust and re0join the main flow alt least 18inches from O2 housing. (I read this in "Maximum Boost" by Corky Bell.)
Any other insite on this? I don't claim to be an expert, just read alot about it.

 

Well I bought a 02 elim. downpipe.... not sure what to tell about it..

 

A guy in town here also bought the RnR O2 elim. He also had issues putting it on. He also detremined the holes didn't line up.
RnR is going to try a work things out and fix the situation. They claim they out source the flanges and that they did them wrong?
Anyway, my B&B DP went on easy.
I am going to take it back off and pull the stock doughnut gasket and replace it with a flat one that doesn't restrict flow. I may even port the O2 housing then.

 

I bought one as well and had no issues at all putting it on other than taking the radiator out to make it easier, but I knew that I would have to do this when I bought it so no issues. I did several modifications at the same time, but the spool-up is quicker.