How to change from legacy sata to ahci on an existing system?

Hello. As most of you probably know, intel is employing a different variant of their driver for legacy ide mode and for 'native sata'/ahci mode. Does someone know a smart (preferably fast) way to change from one to another?
My primary problem being a wds image, or a ghost image, that doesn't deploy on new laptops unless I turn ahci off - effectively reducing the performance on what must be considered an already slow platform.
Someone will at some point in the future tell me how to add more drivers to a wim image, but until such time - is there an easy way to do it?
I was thinking something like booting in legacy mode, update the driver, and reboot - enter bios and turn native mode on - or use a vista dvd to boot from and add the appropriate registries and the driver files manually (did once for a jmicron controller, but is rather complicated).