Hi Bluffer and welcome to the forum.
Specifically, if you were pedaling an Adventure with standard fins at 40 cycles per minute you would be traveling about 7.0 feet/cycle and 5.1 feet/second. But if you had the Turbos, you would be moving smartly at about 9.5 feet/cycle and 6.9 feet/second. That works out to about a 35% difference. It does take a little more effort to push the Turbofins, however; nothing is free.
Speaking of cost, they'll set you back about $80 (PN 72065). They're not difficult to install, but the instructions are not totally complete, so it's possible to screw up a couple of things.
If you overtighten the allenhead screws, it's possible to crack the mast housing. I you overtighten the clew mount screws, you cause the aft sproket protector to bind. This will degrade the performance somewhat and possibly cause the "clew" adjustment to un-thread. Most of this paragraph doesn't apply, however if you have the older style drive (about 3 or more years old?).
Having read this, you know how not to screw it up. The instructions bring the above nomenclature into clarity. So if you can screw a lightbulb in left handed, this should pose no problem. If you are already left handed, you can practically do it with your eyes closed!
