im using halfords oil in my smax,buy it when they have a bogof deal.soz cant remember any details about it but its all written on the tin.lol. havnt used my pump yet on the smax,but i do know the filter is tucked up underneath so yes it is a tray off job, so i found a willing garage to change the filter and use my oil for about 30 quid.as there stock oil wasnt up to the job,thought it was a good deal. and saved my hands from getting dirty.