Having owned an e92 M3 and now an M4 the M4 completely destroys the E92 in relation to outright pace there is no comparison at all.
Once you start tuning then all bets are off the twin turbos in the M4 completely monster the older car and what can be achieved.
Simply using Bootm0d can put the M4 well over 500 bhp for less than €500 however I do agree the noise of the V8 is so much better and I miss that.