Parts Sources for Japan-Made 2000 Accord EX 4 Door

This 2000 EX 4 dr sedan was built in Japan with an F23A1 engine has begun to burn oil and may need an overhaul. I am identifying parts sources prior to disassembling the engine. Honda built this model in both the US and in Japan and some engine parts are different. For example both intake and exhaust valves have different Honda part numbers for the Japanese and the US made engine. However, the valve springs and the spring retainers are the same for both engines. How is that possible?

Can the Honda technicians recommend:

1) Sources of OEM/OES intake and exhaust valves other than the dealer. Beck-Arnley, OSVAT & DUKORO all offer aftermarket valves for this engine but I have no experience with engine parts made by Osvat and DUKORO. How reliable are they? (Sealed Power also offers valves but I suspect they will only fit the engine made in the US, not the Japanese made engine.)

2) Sources of OEM/OES pistons and rings other than the dealer. NPR makes a piston and ring set for this engine and I have good experience using NPR parts in the past. Hastings and Beck Arney offer replacement rings. What has been your experience with NPR, Hastings and Beck Arnley rings and pistons?

3) Sources of OEM/OES main and connecting rod bearings. Taiho made the bearings for this Japan made engine; can Honda technicians recommend a manufacturer of high quality OEM/OES bearings for this Japan made engine?

OEM gaskets are made by Nippon Reinz are widely available.