I used 100" or 30.48 meters and it wasn't enough for my 4-2-1. Here's a thread which some of us added our stories and ideas on the matter. >>>Click me.<<<
The 4-2-1 header I rock came with the B16B I purchased from JHPUSA.com, all it has is a JASMA emissions stamp welded to it. Resembles the Spoon Sports piece a whole lot but whoever had it previously mated this 4-2 piece to that of an oem cast iron 2-1 end which probably explains the longer length perhaps.