Hey op, I know what sound you are talking about..
I just installed catless downpipes on my car, mated with n55 mids.
It sounds really bad.. around 2100 rpm. it goes like ehhhhnnnnngggggg hahahha lol
Also, I'm the type that likes to drive with my windows open as much as possible. But going completely catless, I don't think I can do it.. which is another reason why I'm planning on putting the oem dps back on.
But here is what I was wondering.
If smell or noise isn't the problem, would you go catless downpipes or catless midpipes?