I'm looking to do a few upgrades soon and was wondering if anyone knew some cheap places or some ballpark numbers to give me a idea of what I would be spending

ok first, my exhaust sounds horrible lol. All I know is that the previous owner had a u bend delete done and a high flow cat put on. Also I believe that cat is throwing a 02 sensor code as well. What can I do to make it sound better? Glass pack? Cherry bomb? New mufflers would-be nice whats the cheapest I can go? Also I hear them hissing when I start the car so I know they have holes in them lol

Next is the brake upgrade, I would like to upgrade them to the bigger brake setup. Whats the cheapest I can go? I want the rotors and the 12 in brakes if possible i have searched I just want to know where to get it from? I have a nice hookup at the auto store lol

Thanks guys! Also if I put this in the wrong section I'm sorry is it possible to be moved to the correct section? If so, thanks!