Ummm, I'm pretty sure there is no secret to disassembling the heads, they're just not serviceable. i.e. if you break part of the VVEL system, you're screwed. The VVEL system housing and the cylinder head are machined/cast together so the whole enchilada must be replaced if it breaks. Kind of like some camshaft caps/bridges.
The service manual has procedures right here for stripping the cylinder heads - no special tools required. You just cannot take the VVEL assembly apart without messing sh*t up. I'll post diagrams if you wish, but I'm guessing nobody has bothered porting these cylinder heads because they're likely VERY efficient from the factory. It's a similar situation on the new Mitsu 4B11T heads - simply not worth it to port them unless you're trying to squeeze out that extra 10 WHP.
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'10 PW 370Z 7AT - wife's car - Project Raspberry Cheesecake
'08 Evo X - built motor+trans | BB-X @ 32 psi | CH3OH | self-built+tuned - ??? WHP
'01 Galant V6 - built motor | GT35R | self-built+tuned - 550+ WHP (retired) |