On my Rolls I have not seen much better performance since I have used it rarely, and it is a heavy car with large engine - 6,75 litre.
But it starts much easier. See also above about Javelin and Rambler, and test on my Rolls. My first customer bought MS for his 50-55 year old Mercedes. At a show 3 months later he came up to me and said:"that one works very good". He was going to a "race" for over 50 year old cars, and after driving 150 km he ment it was time to fill petrol. He thought there was something wrong with the pump at the station, it stopped after 9 litres, but the tank was full. The car had never used so little petrol.
I have had problems with starting my snowblower first time evry winther. The petrol was brown and smelled bad. After adding one FuelCatalyst pellet to the tank, it starts much easier, petrol is clear and smells good, and it runs much better. It starts at first stroke and I can turn off choke
at once. Looks like you are from Australia? The manufacturer has an agent there, and one in France. Think there is one in Belgium and Germany.
I use to say about the Spitfire Multispark; It's probably the cheapest horsepowers you can buy.
And you will probably get your money back
several times in saved petrol. It should last over 10 years. ( Always smart to keep the original coil lead in the car, just in case )