I was having the same problems as those above, could not beat tier 3...but i finally got through it. Han and luke both at level 85 gear 8 both needing the last final piece to go to gear 9, so i started changing mods around then made it to second round, changed a few more then finally beat it, it was not easy by any means but it is doable. Your best bet is to change around your mods until you find ones that work. Did the same for leia and got through all the tiers except ben vs vader. Wating for ben to be 7* i am at 66/100 but i hope i am in good shape after some more refreshes tonight. Im excited because i did not think i would beat that tier 3 either.
Oh also i did not have speed mods, it was mostly defense and health for han and crit damage and health for luke. Sucks having to take my arena mods but it is only temporary.