Help don't want forced induction!!!!!

Mjthind

Hey guy I have question which has been disturbing me for the past 2 days. Since my Nismo Z is not arriving till July I have a lot time to plan. I don't want to do down the road of forced induction(any more), I was wondering if what I can do in terms of adding hp to the engine. I was thinking of remapping of the ecu, remapping of the management system(don't know if same as ecu), increasing displacement to 4.0L(custom,),light weight engine internals such as titanium(will have to be done custom) (pistons,piston rods,camshafts,etc.), high-flow exhaust, upgraded exhaust manifolds,,bigger oil cooler,radiator ,and custom heads. How much more hp do you guys thinks these mods will add? Is their anything else I can do or have named every single thing I can do to increase hp without going down the path of forced induction. Can you guys please tell me anything else I can do. It will very helpful with your guys suggestion.
Thanks,
Mjthind