Hi,
Possibly a stupid answers. Sorry for my English
For the plethora of e46 intakes i dont know if is fit, i'm not a expert, but i have read some CSL intake for E46 dont fit why a part of the intake touch the frame, and if you don't have a CSL type with maf housing you must an alfa-n tune programmed.
I find a lot of intake before ordering the EVENTURI INTAKE make by Evolve (I receive it next week).
I have read many review, thread, and my choice is for this intake but you can see below a brand list for Z4M and M3 E46.
Maybe this list can help you.
This list inclued intake with heat shield or directed connected to out.
-EVENTURI for Z4M
-BMC CAI for M3 E46 ref:ACCDASP-06
-GRUPPE M for Z4M
-SIMOTA ref:CF610-32 for Z4M
-AFE for Z4M
-CSL type airbox (Evolve, Ebay, Delage,...)
-BLINE MOTORSPORTS for M3 E46 (! there is not vacum line on the elbow!)
-ECIS for M3 E46 ref:16269
-K&N
-INJEN for M3 E46 (! there is not vacum line on the elbow!)
Good luck for your research.
Have a nice day