I'm not sure what you did, I think you are complicating things without need, AHCI mode should need no extra kext and no extra options at all, if are you installing from SATA to SATA, are you using a PATA DVD or HD? If thats so the thing changes...
I would advise you to try a clean install with no modifications, choose as less options as posible (i.e. you dont need graphics or sound, but you would need a Voodoo kernel or PS/2 if you use that kind of mouse...), and always boot in verbose mode (-v, not v-) so you can report the output instead of just "grey apple logo" or "some error".

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AsRock P45TS | C2D E8200 | GeForce 8600GTS
Mac OS X Snow Leopard 10.6.1 + Windows 7 Ultimate 6.1.7600 + Fedora 11