Is it possible to boost on to an obstacle when using R5-X3? It says ignore obstacles until the end of the round, so I'm assuming yes.

Yup. Unlike Dash, I don't believe that ignoring obstacles is optional.

Agreed, can't be done..

why cant be done ?

maybe this help you more than just a no.

https://community.fantasyflightgames.com/topic/189944-r5-x3/