I don't know anything about the Tornado VV booster except what I found googling. However, it seems to me you would be better off with the Lavatube as you would at least have a second PV for the same price instead of buying something to stick on the top of your current PV.
The Lavatube has some QC problems, but there are a lot of people who love them. Don't expect it to last forever, but it's a fairly cost effective way to try VV.
JMO.......