I would definitely reconsider your plans and any associated costs/quotes/budgets as what you require won't be cheap. I would also recommend a more suitable workshop for such extensive mods, unless you have plenty of time to wait and money to burn.
Teppanyaki for sure! Best fun I have had eating/catching/wearing food in a long while Carlingford is good too with plenty of parking and well priced.
PS, don't wear a suede jacket
I don't see why you couldn't make up an adaptor plate to bolt the RB26 manifolds to the RB25 (or RB20) head. Pretty sure that "Jago" on here has done something similar in his R31. Apexi made a manifold that suits both RB25 and RB26:
Back in the days it was a derelict, neglected and undeveloped area of Sydney. Now that there is $$ involved, the pollies have pushed for a crackdown to eliminate "car hoons".