Many people want to delete their cat either in hopes to save money, make power or to some it almost seems to me as though some macho statement proving how cool they are by not giving a damn about their emissions or the environment.
I won't try to convince the latter group because you can't fix stupid.
As for money you can get a good high flow cat for less than $100. If you are cheap or lazy you could find one that clamps on with a couple muffler clamps.
A good cat should easily last you 5+ years. That's $20 a year to greatly improve your emissions. If you drink coffee, smoke cigarettes, or regularly chew gum you don't want to do a cost comparison on that.
As for the power, this is the big myth. Many people seem to believe that a cat robs their car of enough power to warrant the effort to remove it. This is simply not true. The only time a cat will be a notable restriction is when it is clogged. At that point just buy a new cat.
Now it is possible for a cat to slightly change the characteristics of an exhaust system and therefore a power curve. Therefore in some tests you might see a small loss in one area and a small gain in others. In some tests you might see a small gain or a small loss across the board but not enough to be worth noting unless you are racing competitively.
http://bobsmuffler.com/cattest1.htm
http://www.easterncatalytic.com/product ... n-results/
http://www.hotrod.com/how-to/engine/ctr ... dyno-test/
http://store.uucmotorwerks.com/articles/catless.htm
If you are really chasing more power focus on mods that will actually give you more power. Have a little respect for the environment and your fellow earth dwellers, keep the cat and change it out if it may be dead or clogged.
