348 Gearbox Mounting Bush replacement

Does anyone have experience changing the gearbox mounting bushes themselves? Part no. 139230 - scuderiaparts seem to have them way cheaper than anywhere elsewhere...

I see there's a plate under the airbox linking the pair of them them with the subframe - can this be removed and the bushes changed in-situ by supporting the gearbox underneath etc? I know some bushes can require pressing in etc so I wanted to see if people have had success doing this in the bay, or if it's best left for engine out service.