my son has a HQ prem with gas and it runs really well but we have only had it running on gas not duel fuel,but...under the bonnet is a real mess and when i took it off to change the air cleaner they had used a heap of silicon to seal it to the carby so we will be taking it off soon . i dont know how old it is but im sure a new gas system would be much neater so it might pay to shop around and not buy the cheapest system or a second hand one