Ok, so as I get the same question all the time, here is the answer.
The mod is a simple unscrew the old ones and rescrew the new ones, that's all.
The difference is so huge, that you'll ask yourself is it still the same amp ?
Way far better, powerfuller and preciser bass. A better definition all across the bandwidth which will be wider and way more headroom.
It's a "winning on all sides" easy mod, but don't forget to respect the speakers polarity.
You can even disconnect totally the speakon output to be sure.
These Fane Sovereign 8-225 were the mod speakers used in the SWR Baby Blue to improve this already excellent combo, just in case.
Hope this will help everyone.