i think i speak for most people mate when i say how longs a peice of string ,
you could ask 5 different tuners what they would spec for 500 hp , and i gaurentee they will all have there own ways /spec of achiveing it ,


best advice is consult them , find one that explains there price , and comes with a good reputation ,

and spend your money with them ,

if your capeable of building it , consult them or whover you plan to map it ,

but remeber theres not likely to be a gaurentee when you built it yourself



good luck with it

beef