just to clarify.
this is a original vipec plug and play board for SKYLINE RB.
It supports all RB's including R34 GTR via dip switches, so rb20 rb25 rb26, EXCEPT IT DOES NOT SUPPORT R34 GTT NEO.
It has does not require any extra harness's for supporting a 6 cyl, it does that standard, those extra cables there is the expansion cable which allows you to connect extra aux devices / temp sensors ($50 add on or something)
it has full boost control, you just connect it to where the original one was in the first place.
it has a inbuilt map sensor also, its a true plug in solution for RB skyline.
this ecu is HIGHLY capable when in the hands of a tuner that knows what they are doing with them, can work well with 150kw to 1000kw + setups.
hope this helps.