Board Thread:Game Discussion/@comment-154281-20130514121853/@comment-9477730-20130514155923

I agree with Kiwi999

Right now, try to get a ranking that will 1 or 2 bosses & MTM them in the next event. Your stack will build up within 2-3 events.

If you don't want to spend at all, then MTM  (Max alt & Max Rbt, Transscan, Max) Starscream/Grimlock/Prime using the Sliver & gold metals you get. As you open those metals up, R4 card would pop-up 1 in 200-500 (esp with silver).

For $1, The Raid Divebomb card in Alt mode maxed (without bonus) equals to a MTM Grimlock. So it will still quite helpful after the event with your current stack.