First and foremost,before i install the jrsc on my ef7.5,this kit were install in an ek4 before the ek4 were scrapped and that was running on a stock ecu(obd2) without any idle problem.As a layman's theory,i would assume that it'll fit into newer ecu's like obd1 or 2 without any management.As for my ef7.5,it's running on an obd0 ecu,so there's a need for a piggyback ecu in order to get the engine back to stock idle after installing the jrsc.And for the hp gain,it'll be around 30-50hp depending on your mod(for standard jrsc-6psi).Bro "akuma",complete means it comes in a set(only jrsc),like you buy it brand new,just that i'd used on my ek4 and ef7.5 and if you buy it online,it doesn't come with any management either,that's optional.Bro "pok nik",do a search in goggle or yahoo,you could see tonnes of links and infos of it.I'm selling it off as i'm running on n/a mods currently.Just give bro "XXXX" a ring if you're really interested.Thanks and hope this reply does clear some of your doubts.Cheers and happy rexxing!