Catalytic converters and their effect

Here a couple of questions that have been on my mind:

-What is the affect of a catalytic converter (cat) on a down pipe?
-What is the affect of a cat on a CBE?
-How do cats affect tuning?
-Does running catless cause flames to shoot out of the exhaust?
-Do cats control boost throughout the powerband?

Now mind you, I have no knowledge of cats and what their purpose are. My car has a 3" open bellmouth catless TBE.

Definitely looking forward to seeing what you guys have to say! :tup:

Holy shit... How many ACTUAL tuners in the Big Name Brand world are there that actually know how to tune?! I can't believe how ridiculous this is knowing all this information now. Damn scammers and swindlers! I wish I could have known all this information right when I bought my car. I truly cannot wait to see what George has to say.

I think Edwin's assessment is accurate

I feel cats are a matter of preference though. Either way they have little effect on the tuning process per say. If it is numbers you are after then go catless and if it is being responsible to the environment then go cat. What ever decision you make the tuner should work around it. What ever tune you end up with will be optimized for the hardware you are running at the time. The difference in power aint gonna be that much either until you start getting up there in turbo size and horse power. My car was making just over 500whp before it shit the bed for the last time and it had a catted invidia down pipe.