KMPH to MPH conversion

[ringram]

Hi guys, I know I can cludge the speedo by messing with the diff ratio's so that it looks like its gone from kmph to mph, but the ECM VSS PID reads from elsewhere doesnt it?

Can I make some changes to change VSS and the speedo needle so they both read MPH and also so things like the auto trans etc, shift at the right points?

Or do I need to do some hardware changes too?

Thanks
Richard

[ringram]

Can I leave the diff settings as is and mess with H0105 instead?
I read a few threads suggesting this might be a go. How will this affect the odometer? Can I adjust it by a factor of 1.6 to convert to MPH.

I think this might be more on the right track, I just need to know what happens to the odometer.