go to MKIV.com under TECH section. HKS EZ should be installed the same as Blitz boost controller. I was told the supra supplement installation guide which connects to pressure tank over boosts #1 turbo and will hurt #2 turbo. so the best way is just to hook it all up to #1 turbo and wastegate.
as for head unit, all yo need is 12V power source and ground.
as for head unit, all yo need is 12V power source and ground.