Whats cheaper? to buy the apex-i n1 full cat back exaust or just buy the n1 muffler and have a shop do custom piping thats 2.5 inches? and what is probably better?

 

Just call around and get some estimates, your trouble will be finding an inexpensive shop that does mandrel bends. BTW, Apex-i doesn't make 2.5" piping, just 2.25" and 3" for turbo...at least in the US that I'm aware of.

 

Most Meineke shops can do a custom exhaust for you and weld on your muffler. It'll be a little pricey but I am not sure how much. 2.5" maybe too big if you are NA depending on your mods.