anyone knows what's the performance difference between the novarossi 51607 pipe (6mm stinger) and the nova efra 2630 pipe (5mm stinger) in terms of fuel efficiency and power (low or top end pipe) ?

also, does a 5 port .12 size engine means better suited to an exhaust(51607) with 6mm stinger and 3 port engine should use a exhaust(efra 2630) with 5mm stinger ? many thanks...