Removed the Perkos and installed the complete set the Southcos on my 2006 P4 last night. Talk about very nice. Very smooth operating. No drilling or filing required for installation Just a #2 phillips, 11/16″ wrenches and some lock tite. I also put the flat o-ring on top and the hard ring on the bottom. That seemed to be correct. There was no instructions. Super easy install. I will have some Perkos for sale cheap if anyone is interested. I will be at Teals Point for the OI.Last edited by brewcat on April 22nd, 2011, 2:07 pm, edited 1 time in total.