I would recommend it, when I went from OEM to yellow powerflex it felt way better/tighter when changing gears. We did fit the torque arm, upper and lower powerflex mounts at the same time though so couldn't comment on whether you'd get much extra vibration with just that one.
The worst bit was just getting the gearbox to release from the mount, the first time i did it i soaked it in wd40, jacked the gearbox up and down, jumped on the door sill and it wouldn't budge. Eventually it released by itself after about 30mins when i gave up and started to pack up.
Second time round i used a pry bar to separate it but that was with the front end off so might not be room for that normally.
Run the nut up so it is overhanging the top put a socket on it and hit the socket make sure there is something to support the gearbox underneath but do you see the base plate that has moved on the two nuts I think a washer with a centering collar is needed I've noticed most of the suspension stuff the bolts don't fill out properly and you can see witness marks of the treads on the inside walls the bolt goes through like the bottom engine mount and the lower arm bushes not point having poly bushes when there is 1-2mm of play in the bolt.