been said earlier in the thread - but the worry is fully-synth 'car' oil - which has friction reducers and messes up the clutch on bikes - bike specific, fully-synth oil will be fine.
I always use castrol R4 in all my bikes - its very good value (under £30 for 4 litres - even from halfords!) which allows me to change it twice a year on the sports bike if I feel like it.
I always change filter too - with every oil change, but interestingly, the schedule on the strom doesn't require it - I still will though, doesn't make sense to me - the filter is what, £6? - and it holds 1/4 litre of old oil.