are you talking the plastic mesh or the metal mesh?
I prefer the metal mesh and you can buy it at any speed shop for like $20
you just have to cut it to the right shape and clip it on i believe.
'94 Supercharged E36 325is (150,000 original km's)
-Vortech V9 G-Trim @ ~10psi w/ BOV
-255LPH Walbro fuel pump
-TEIN SS Coilovers w/ Pillowball mounts
-Keskin KT1 17x8.5 & 17x10
-Remus full catback
-Authentic Rieger Infinity I body kit
-SMT6 EMS (Untuned)