Dahlquist crossover upgrade from Regnar?

Has anyone upgraded their old Dahlquist speakers with the crossover kit available from Regnar? I have a pair of M-905s which I still love, but I’m curious to know if the upgrade kit makes an appreciable difference in the sound quality?

Also, how tricky is the installation? Can’t be too bad (ha, famous last words…), but if there are any tips or tricks you can share, please send them my way.

If anyone has experience with this I’ll appreciate hearing your thoughts. Thanks in advance!