Wow missed a lot have I not........
The CAI is not about performance it's about drive ability on the M44, the standard air intake starts from the left hand side (driver in uk) goes up over the radiator, down and up into the air box, this causes a stutter around 3000-3500 revs and then the car seems to take off up to redline, the CAI is just one of the options, to remove the convoluted air intake, you can also FOG the original air box
http://bmwz3diys.weebly.com/fogged-air-box-mod-19-m44.html
Both give the same result, one gives you an intake growl though
Doing this gives you smooth delivery right up to red line.
You don't need to go to DASC for extra power, in order to get sub 9 second performance, just fog your air box, fit a free flow exhaust, have it chipped and fit a single mass aluminium flywheel. This will give the impression of adding 25bhp to your car overall
This will put a grin on any M44 owners face