Having heard the Simota and AFE intakes on numerous 6 pots inc M3's I can honestly say they sound amazing and provide notable difference to throttle response. The Simota kits for the E46 M3's come with the cone filter housed in a genuine carbon fibre surround and also a genuine carbon fibre air intake that mounts on the front panel under the bonnet and runs back to the filter. These are €576.00 each. See link below, on a side note Simota claim a 12hp increase on the E46 M3.

Simota CAI

If any one is interested Schmiedmann have 3 SIMOTA in stock which I can offer with a 10% discount making the Simota CAI €522.17 with lead time of 3-5 working days.

Below are links to AFE's offerings, if any one has any questions at all just ask and I shall be more than happy to help where best I can.

AFE Pro-5R stage 1

AFE Pro-5R Stage 2

AFE Pro-5R Super stock


Hope this helps,