Can't remotely speculate on what modifications will benefit the engine or what can be done. At this point there are so many variables and no conclusive data to go off of.
Generally speaking:
Increase Engine Breathing: IM, CAI, header/exhaust manifold, exhaust system, camshaft, port and polish head, valve work and valve-springs (latter for RPM).
Increase Fuel Delivery and Ignition: ECM, injectors, fuel pump, spark plugs, high compression pistons
Reduce Inertia Weight: Lighter and stronger internal components, pistons, connecting rods, crankshaft, blueprint (internal weight and friction distribution)
Reduce Friction: Piston rings/cylinder liners, smaller bearing and component widths (will need added strength to components).
Increase Lubrication: High output oil pump is required for drastic RPM increases.
Increase Cooling Capacity: Water pump, radiator, thermostat.
There are others but this is generally speaking.
Making more power to a naturally aspirated engine means you want torque higher in the RPM band to produce horsepower, consequently you will be looking for RPM gains and those need internal tinkering and work if you really want something.
Raising the Redline of a stock engine doesn't really do a whole hell of a lot. It's out of the power band (for various reasons), and producing unneeded stresses on the internals.
Lets say some dumb a** raised and tuned only the fuel cutoff (redline) +1000 to 9200rpm of a bone stock 2ZZ-GE. What happens??? Maximum torque and horsepower are the same stock values at same RPM. Power significantly nosedives after 8400rpm and valve float begins appearing, at 8800rpm there is a noise and significant loss of power; that noise is the piston colliding with the valves. The previous also happens if the dumb a** misses his 5-6 shift at redline and goes 5-4
.
At continuos 8500rpm for periods of time there is a good possibility of the oil pump disintegrating (2ZZ have notoriously weak oil pumps), stretched connecting rods, and severely increased bearing wear.
I wouldn't touch a redline increase (on any engine) until a decent amount of components have been improved and optimized so that the engine can sustain the increase.
Rant over I guess...