ottomann

2 weeks ago,about 1 mo.after changing exhaust and doing intake mods my 01 225qc, I began hearing a fluttering hiss at a closed throttle after reving the engine to 4000 rpm or so when accelerating. I am not sure this isn't due to noise transmitted through the extra intake snorkle I installed. This morning, when I first started the engine,the turbo seemed louder than normal as it spooled up after first starting. About 30 secs. later the check engine light came on. Car seemed to drive O.K., maybe a little surgy. Are these classic symptoms of a faulty D/V ? Car just turned 7000 mi.