If its daily driving with the occasional blast then you will be fine with 10W40... I use Motul 15W50 myself as i only drive it on weekends and try my best to drive the stones out of it... Either will be fine for you..
I think its recommended to change every 5,000kms... Thats how often I'd aim to do it anyway... Possibly more, but someone may be able to better advise you on that