What do you think is a good size for exhuast piping? I'm eventually going to use a 2.0L engine. My exhuast system is pretty old and rusty so it needs replacement anyways. I was wondering if 2.75 inches is too large? Or what does everyone think? Thanks guys

i believe 2.25-2.50 inches is the recommended size for a naturally aspirated car...and if you're planning to run a turbo i think it's recommended to have atleast 3.0 inches...

You have to be carefull when deciding upon a pipe diameter, especially with a turbo. Both too wide and too narrow can have a detrimental effect on your engines performance, I did a little bit of checking and the size you mentioned 2.75 inches is useable but 2.5 inches seems to be the best. If you have a turbo you will have to check further.