As Tom and Bing said,it is designed to be driven sounding angry,lol...and grabbed by the scruff of the neck.
I spend most spirited runs,Nationals etc etc ,in 3rd gear at between 3k and 7/8k revs,as max power is about 7-7.7k rpm,just below where the limiter kicks in,so you need to get used to that and time your changes so the limiter doesn't hit.
I love mine,but understand where you are coming from.
For me,the M beats the 3.0 in every department,and while the engine is more vocal(especially above 3000rpm), wouldn't swap it for a 3.0i z4 e85/86 ever.
As Bing mentioned, you need to stop thinking you are doing it harm(as long as it's warmed upto 90/100c on the temp gauge,etc) it's fine to put your foot down.
I do remember when I got mine,asking John(sammyz),if his sound so "metallic" and gallery sounding as mine did,and if that was normal,to which the answer was,his sounded the same,as it's how it's meant to sound
I only use mine in higher gears when using it normally,i. E not on runs.....above 3000/5000 rpm is a great place to be,as it sounds like the racing engine that it is......and starts to drown out the exhaust

By that I mean u get the nice exhaust note,burble and backfire upto a certain rpm,then all you here higher up is glorious engine noise......I rarely listen to my stereo on a forum run
