is there any risk if i take my catalic converter and muffler of my F250 99 powerstroke diesel 7.3

 

It depends on what risk you are worried about. The only risk with removing these parts would be with emissions laws. taking the catalytic converter off is the illegal part about it. though i know many many people that take them off and have never gotten into trouble with the state. if you do get caught they will only slap you with a fine. As to risks with the truck there are none. If done correctly (whole turbo back system with larger diameter pipe) it will give you quicker turbo spool up time, reduced back pressure, cooler exhaust temperature, and a sweet *** sound. A friend of mine has a 99 7.3 and has a 6 inch turbo back system with a 7 in tip behind the rear tire. it runs great and sounds pretty cool. i will warn you that if you do not want a very loud truck than add a muffler option with an aftermarket package. They are greatly improved over stock mufflers because they feature a straight flow design. i mean that you put your arm straight through it to the other side. usually no matter which way you go you will have a clearly defined turbo whine that usually turns many heads.

 

well it has the 3 1/2 stock but they told me from the turbo it has a 2 inch downpipe they said that the biggest one i could put from there would be a 3 1/2 and then whatever inch exhaust from there on

 

Really its the bigger the better. they say that 3.5 is the biggest mostly because of clearance issues with the firewall. it must be very hard for the engine to push that much air through a 2 in pipe. a 3.5 in dp would make a big difference in power, temp and sound. most systems have a 3 or 3.5 in dp and then go to whatever size. i wouldn't go any smaller than four in though. if you plan on any other mods such as tuner(s) i would go with 5 because it will keep egts lower after adding more fuel.