Just installed the Euro box + K&N E-2022
about 2 hrs. ago and definitely felt a difference in my 330 coming from bone stock. There is a bit more engine noise, especially at idle and higher rpms. Car seems to deliver power a bit quicker and more smoothly, though this could be just because it's nice and cool outside
Biggest improvement--since I bought my car 5 months ago, the idle wasn't stable. Nothing crazy and no CELs, but I wasn't satisfied that it wasn't perfect. The one time I was at BMW (not under warranty), they said this was normal and nothing to worry about. Needle hesitated in park, neutral, drive, cold or warm engine (tried removing all possible A/C drains as well, recently replaced spark plugs). I thought I needed to have my engine checked for timing, etc.
After installing the intake, the engine now idles at 580-600 rpm, completely stable! Absolutely no hesitation, even if I blast AC/heat. I think I'm just more relieved that it wasn't a more serious issue... On another note, I went from completely stock, so a carbon delete and/or K&N drop in could have cured the hesitation as well.
I bought my intake here
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT , got a bit lucky that I had a friend fly to England within a week of the listing. Not sure I would have dished out the $$$ ECS charges...
...can't wait to hear my car once the BMW Perf. muffler I have sitting here is welded on!