well - I'm certainly not any expert on exhausts however my comparison is the Toyosport stainless system that I had on before. Currently, the exhaust sound is fine but at 2500 to 2800 it becomes more acute - what I would call a low grade drone. When the holes were 15mm this was hardly noticeable however now I have taken them to 25mm is has become annoying. Certainly not extreme like before however I guess it depends how fussy you are
It may also vary between different cars / engines / models / etc.
