does replaceing my stock cat with a high flow one make my truck louder an run better,or will it do nothing at all

 

i heard they work great for our trucks. but i havnt goten one yet because it will be 450 because of BS emissions laws in california

 

Made mine a little louder, and noticed a small gain at high rpm.

 

does it mess up or throw off the o2 sensor

 

No, but it is not uncommon to have the o2 sensor get stripped when you try to remove it from the stock cat to put into the new cat, making it worthless. I had to buy a new o2 sensor when I did mine for this reason. Just be prepared that this could happen (added $$$).

 

my O2 senser is about 5 inches in front of the cat,i dont have to fool with it