Had one, sold it. Made no difference to performance. Waste of money
ph1 I did some engine work on was mapped last week. Due to coming with a crappy cone, it had a ph2 airbox fitted. made mediocre bhp and decent torque. A Maxogen (which I've always rated as far too expensive for the gains) went on and with minor map tweaks it made another 8bhp!!
ph2 airbox is a noise limitation exercise