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Hello and welcome.
JDM or EUDM should not really matter. On 95 octane fuel, you‘re better off with 10.5:1.
I would not rev a stock piston/rods k24 higher than 7500 and a build one 8000 rpm.
A build engine will take some 8500 for a few seconds here and there, but not sustained switch point on circuit track days. At 8000 rpm we talk Formula1 piston speeds. And they count engine life in hours.
R1 ITBs are actually too restrictive for a build k24. Due to the VTEC system there is no need for ITBs. A decent plenum works well.
Check adds for 2nd hand sk2 ultra street intakes. I think they can be used for RWD applications.

If you go SC or turbo, there is no need to build the engine even for 400-450HP. Keep the revs low.
You don‘t even need to change the cams.
If you find a 2nd hand JRSC kit, they will push 300HP on a stock k24 or k20, 350 charge cooled without a single internal engine mod. On a k24, you will also get a LOT of torque.

if you want to build a 9000 rpm k24 reliable daily, forget it. For 9k rpm, you need a k20. Piston speeds.
This is unless you only do drag racing and a couple of 1/4 mile runs per year or per rebuild.

if you want reliability and power, slap on a SC and be done with it.
No fancy electronic pulley needed. The common SC kits run the throttle body before the SC. This essentially lets the rotors spin in vacuum most of the time with minimal mpg losses in daily use.

For such a SC set-up, a stock engine loom and a Doctronic ECU is all it takes. No need for a fancy EMU ECU. Saves a lot of quids.
All these „tucked“ looms are for USDM market cars that use different wiring for their lambda sensors.

For fuel control, you can use a wideband before the cat. The second lambda is supposed by Doctronic, but is only required for emissions reasons. It tests the cat converter efficiency by measuring its oxygen storage capability.

if you get unhappy with a 300 or 350HP CC SC set-ups you can pick up from 1500 to 2500 quids 2nd hand, you can always order a big Mercracing SC, slap it on and sell the MP62 SC kit for the same money you paid for.

The fuel system is dictated by the fuel demand. Unless you know how much fuel the RX8 system can deliver at what pressure, no one can answer this.

For a 450HPO build, you need a meaty pump and I‘d strongly recommend a flow-through system.

Top tip: do it right at once. Prep the car as you intend, but only skip the SC if your budget is constrained.
This can be added later. If you first go stock, you have to spend a lot to make a NA screamer with ITBs, ECU, forged rods and pistons and expensive cams only to swap it all out again for your SC upgrade.

Stock k24 with suitable cams and springs gives you some 260HP
stock k24 with simple MP62 SC kit, no charge cooling yields you effortless 300HP with stock reliability.
add CC to get 350HP. Keep the rpm limit at 7500. The SC k24 will effortlessly rev to 8k and higher, but WILL fail in short order.
Stock k24, no internal mods whatsoever, you give you 450HP with more boost. For circuit track use or sustained autobahn speeds, you need to open the ring gaps at such power levels.

I suggest you spend a couple of hours searching here. It was all covered.

if you project depends on saving 300 quids for a suitable intake, I‘d stick to a most basic conversion.
It is easy to dump 15k+ quids into an engine conversion doing it nicely.
Don‘t ask me how I know.

 

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Doctronic converts Honda ECU to make it programmable for half the cost of Hondata.
Also no daughter board to fail in there.
Doctronic.at

conversion schematics are in their download section

 

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For 7500 rpm you also don’t need to change the oil pump.
k24 needs forged bits, oil pump etc for sustained 8k rpm and k20 for more than 8.6k . All stock k20a2 owners I know with SC usually switch gear at8k on track and only use the 8600 once in a while.

mine is a build k20a2 and limited to 9200rpm, but I usually switch at 8k and a bit.

if you want the revs, go k20a2.
If you want the torque, go k24

 

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Pressure seems ok. Flow is the next question.
There must be lots of threads on rx8 turbo conversions. They all need fuel for their power goal.

 

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SELOC, eBay, etc

 

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it is all a question of space. You cannot turn the SC around.

The inlet ends about where the block ends. Then you need to feed it air.
You could make a custom inlet to point the TB elsewhere or even relocate it.

 

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if you get an RSP intake manifold, you could build a custom lid for it with the TB flange wherever you want it. That was done here on k20a.org
Cut of the TB flange and close it. Reweld it on a suitable lid.