I need a New 3" CAT, as mine has **** itself, (buzzes & humms) Looking at $350 to replace.. (sound about right?) Also, I was looking at getting the exhaust shop (while its in there) to make up a custom 3" dump pipe from the Turbo to the CAT. They said they just slice the back off the dump pipe just leaving the Mounting plate, then wack a 3" pipe off that. Cost: $350 ok.. Does the bigger dump pipe make that much of a difference?? I realise every little thing added together can improve HP alltogether, but if its really not that big a difference, should I even bother? Its only $350 i know, but that time of year and all.. things are a bit tight. What do ya think?? Thanks

larger dump=less prssure on the turbine=lower shaft speed for same boost your compressor will last longer, and will pump air more efficiently, youll gain power, and the car will prolly run more efficiently as well. all up, it will likely save you money in the long term.

There is a lip just inside your std dump pipe, grind that back and there will be not that much of a difference between the 3" and yours.

350 just to replcae a cat???? why dont you just get them to do the dump pipe for the 350 or so dollars and your cat out yourself and just gut it? Cheers Petros

I made a custom 3inch dump pipe with seperate wastegate( which gets plumbed back in about 400mm down the pipe) and there is a major difference to the car goes and sounds so it is worth getting one.

i can vouch for that fact that grinding the lip made a noticeable improvement, u would think a 3 inch dump would be better again