Two team who got banned for 2 yrs CSK and RR are in playoffs , so you can see the power of fixing in all IPL series.
I am sure there is some form of fixed matches being going on in this extravaganza but i do not think that these two banned teams are in the playoffs simply because of fixing, they just performed just enough to reach this situation and CSK is always a power house and under the leadership of Dhoni they are just performing as usual so it is not that stunning that they are in this playoff and they might even win the entire tournament after the ban.
You are right both teams are very strong and good no one can complain about fixing for playoffs because they play very professionally and reach here some peoples need to grow up for understanding this all because all league cannot be hijacked by fixers just 3 or 4 matches can give them enough to enjoy all year in this business