E46 pillar fabric failure is well known but here is a definitive guide to what is failing and where to get the correct fabric to repair.

BM134 for headliner @ $42/yd - 3 yds should be sufficient for a coupe or sedan

BM3109 for pillars and parcel shelf @ $35/yd - 1yd for pillars - maybe 1.5 to do parcel shelf as well.

https://www.veteranco.com

Veteran Company
620 GLADYS AVE, LOS ANGELES, CA 90021
(800) 524-3330

I believe prices are similar here as well:

http://www.globalupholstery.com/produ...

Global Upholstery Supply
1445 S Allec St
Anaheim CA 92805

Tel: (714) 708-2220
[email protected]

If anyone else has other local or online sources feel free to leave in the comments.