I'm going to give you a "maybe". In all my experience with alternate reed material other than stainless steel, it works on SOME applications and not others. Your motor really shouldn't be allowed to turn above 5250 rpm, due to a harmonic imbalance that could result in flywheel / crankshaft breakage. They simply will not give you the extra thrust to put on a larger pitch prop, that might be necessary to keep it below that number. Will it give you some gain? Possibly........not enough in my book to warrant the change.
V-6 Mercs for example do benefit, because there is an rpm override capability, that the extra flow capacity of the reeds will assist in achieving. On the older 2.4 litre engines, I remember dyno printouts where the reeds alone were worth 50 horsepower. BUT....Where the motor was designed to produce 200 horsepower between 5000-6000 rpm, it would tail off to about 150 at mid-6000rpm values....the reeds due to the free-flowing capability, brought the horsepower back to the 200 hp range. Now consider that you can now run that motor into the mid-6000 rpm range and still have the motor PULL, with a smaller prop, for better acceleration, and now more top end as well. Too bad those days are gone with the advent of rev-limiters. Ok, enough rambling....
What it DOES deliver is a safety margin that could save your powerhead. If you spit a plastic reed, it will be merely spit out through the exhaust port. Chip or fracture a stainless reed, and all kinds of nasty things can happen...up to and including powerhead failure. Good thing that they are pretty reliable. If it were my 125......I would probably leave it alone. :unsure:
