AREA P
3.1cm = diameter at exhaust port outlet
49cm = left header length
47cm = right header length
3.8cm = diameter after merge
4.5cm = diameter just before muffler
AreaP uses 304-stainless and has welded-on flange section that goes into exhaust-port. It has largest header diameter which also merges into pipe of 1.5x cross-sectional area. Note design of merge doesn’t use collector and is not as smooth for flow and lack of cone transition to muffler. Welds are also not very nice or consistent. No mid-pipe hanger and no bung for wideband.