Both cars are performing admirably but there was a problem... the BMW M4 seems still is unfinished atm and when tested for each runs, the M4 smashed out the RS5 by 2 seconds-ish (Suzuka, BMW M4 DTM FL: 1:47.532, Audi RS5 DTM FL: 1:49.466), and when I looked at setup menu, it seems the BMW M4 DTM is not fully rebuilt and included the Power option, Apart from that, the Audi (which become the main car) drives gracefully and just great, so just keep it up and try to finish the M4 DTM further so I can fully enjoy it.
Some funny recommendation, considering the Class One vehicles should be capable of matching each other's capabilities, might suggest try matching pace of Super GT's GT500 cars, so when possible, we can make a fantasy out of it :p