Exhaust questions

[RunnerUp]

ok, so awhile back my cat. met a rock or log at some point and is broken. it doesnt do anything except rattle, i havent had any sensor issues, and cant think of any issues that it would cause. toyota says i need to replace it, and they say they want 1100 for the cat. im not really willing to replace it because it doesnt affect anything that i can see, so i was wondering what reshaping the cat to look more like a straight pipe would do? i want to get the borla cat back exhaust, maybe some downey headers down the road... just wondering what that "reshaping" would do, make it louder? throw a sensor? decrease hp?

thanks guys

 

[sharp4runr]

If it ain't broke, don't fix it. I mean it isn't thowing an CEL or trouble codes so why bother. Also you could buy an aftermarket higher flowing CAT if you do end up replacing it. Check out a company called Random Technologies.