to easy mate, btw vac leaks and boost leaks are 2 different things but if you have a leak at vac you will with pressure. you will need a pressure tester to put into your intake, force air in and when you close the valve you will hear air coming out in all sorts of places, i had no leaks at 5 psi but then leaks at 20psi. things like hose clamps/ split hoses, gaskets etc. then after there fix, it will pay to check it every 6 months or whatever. ask your tuner if they can perform this, if they dont no what your on about get another tuner.
maps are locked, unless at hot idle or cruising then it switches to closed loop and reads the o2 to calculate a/f ratio.
its really shit because if the car knocks, it doesn't retard timing. it just follows the map!!! something that comes in handy on steep inclines, burnouts and hot days which shoot knock readings up from engine load. not sure if other ecus do it like vipec/haltec, motec, wolf v2, nistune piggy back blah blah