I too feel a little pinch thinking that the M3 will be going turbo. But I cannot find any rational argument for it. Looking back at motor-sport history, there is a huge heritage of great turbo cars: F-1, Sport prototype, Champ car, WRC, etc.. so there goes the argument about turbos not being pure in terms of tracking or motor sport.
I think what disturbs the most, is the thought of BMW simply adapting a "standard" engine to an ///M application (like on X5M, X6M, 1M and F10 M5). Historically, the ///M division have built their own engines. And what great engine they were
, winning awards year after year. While I understand that previous ///M engines have started somewhere from a "standard" baseline, the transformations were extensive.
So if ///M builds their own engine (mostly) from the ground-up for the new M3/M4, I guess I'll be OK with it, turbo or not.
If it is simply an adapted N54 or N55, then meh
... it leaves me a little cold.