Difference between APR 2.5" and 3" downpipes

[TazzyVR6]

Hey,

I've got an APR 3" downpipe and was wondering on the differences between it and the 2.5" downpipe. I ask because to my knowledge the 3" is LHD specific and I was wondering if the 3" could be modified to fit a RHD car.

Thanks,
Alex