Mazda MX5 service and rolling road results

We had 34,000 original miles on our 1600cc Mk2 Mazda MX5 that needed a service. We put it on our MAHA rolling road before hand in order to set a bench mark. We got a result of 114.8bhp. We then carried out a basic service which included air filter, fuel filter oil filter, engine oil and spark plugs. After the service we went back in the rolling road for another power run. We found the engine gave a little more power at around 2400rpm. We tried changing the plug gaps and found .044″ to be the optimum with a 1bhp increase in maximum power to 115.8bhp. On the road the car felt better with a smoother delivery of power.