c.e.l. elminator problem

i thought about just using the c.e.l. eliminator to prevent loss of power with the addition of a downpipe. then i heard that the eliminator can potentially cause problems down the line.

my buddy told me:

the problem is that your OBDII car looks for the difference between the two O2 voltages to see how efficiently it's cleaning the exhaust. your front o2 will see a constant signal that is real, the rear one is always the same. i know on domestics they start to run like shit, because they "learn" to run with that MIL eliminator installed. that's why a lot of guys have to reset their computer all the time. the adaptive driving (learning) portion of your computer will belive that your o2 is broken.

is this true?

should i even mess with the c.e.l. eliminator?

also if i don't eliminate the 2nd cat, or midpipe, will i even need the c.e.l. eliminator?

I've never heard of this problem with N/A cars, but I don't have very much knowledge of tuning a turbo car. I'd go to www.rallitek.com and email Sean (I think that's his name). They seem to know their stuff there, as they aren't just selling parts. They do a lot of tuning to Subarus on site. Good guys, and I'm sure they'll be willing to help.

Edit: It might be worth it to come back here and post what they tell you for other people's future reference.

if you leave the 3d cat you will not need a cel fix but if you do there are some ways to avoid these probs ECU tuning is the best but you can also use the MX fix the site mentioned above has them they are 30bucks and will fix it