Using 4 ohm Version When Project Calls For 8 ohm Version

And vice versa. I have the SB16PFCR25-4 on hand and I'm interested in Michael Chua's projects that use the 8 ohm version. Rather than purchase the 8 ohm version, is there a simple adjustment I can make to the crossover to allow me to use what I have? Thanks for any and all suggestions. His contributions to DIY are amazing.
 
You'd need to follow something like this path: Half L values and double C values in the woofer crossover; Adjust Tweeter padding to suit the different sensitivity of the driver; Re-tune the box to suit the new driver (In my experience, 4 ohm 'versions' of a driver aren't just clones of the 8 ohm version, they usually model somewhat differently). Might as well start from scratch. Or, just buy the SB16PFCR25-8, they're not very expensive.