HydrosPlus is in the process of building a bolt-on turbocharger system for "recent" Kubota BX tractors and has a series of videos documenting the process. So far they seem to be running an 80% increase in PTO power.
(this isn't their most recent video on the BX Turbo project, but it explains the project in detail):
(this isn't their most recent video on the BX Turbo project, but it explains the project in detail):
