I have the same issues and honestly I think it is completely normal as well. If you have catless downpipes atleast, then this should be a thing of the norm. If you have stock downpipes then I dont think the car would do this. Nothing to worry about
A/W E92 335i M-sport with JB4 G5 ISO/ E40 WEDGE PERFORMANCE BACKEND FLASH, Alpina TCU flash for AT/Switch-tronic +AR Downpipes, Stett gen 1 intake, Wagner-Tuning FMIC+RB Turbo setup/ RB PCV Valve+ Akro exhaust+60% E85/93 mix,+ HRE P40S wheels, KW coilovers, M3 sways,+BMW performance CF Mirrors, BMW Performance CF deck lid spoiler,+ CF interior trim, p3 vent boost gauge,+ LUX angel eyes (11.73@119mph on street tires) NO METH!