Talk:Lotus Exige 360 Cup Championship/@comment-144.230.63.36-20160713205726/@comment-27123099-20160714153511

It will unlock after you complete this series.

Sounds like you haven't unlocked the Euro Supercar Duel either (or at least not played much of it anyhow). The Wiki says you need to have 14 trophies in Euro Supercar Duel to unlock the 6cyl Mastery Series. Either option will work, complete this TLS or gain 14 trophies in Euro Supercar Duel.