$2k for HUD would be worth it if it can be read with polarized sun glasses at least. BMW would never bring the HUD to the 3 unless competition forced it to, they don't want to lose 7 series customers.
CDT Audio HD-42 component, CDT ES-06 6.5" Woofers in Custom Front Pods, Hertz EBX202R Dual 8" Ported trunk enclosure. Phoenix Gold RSd 500.4 to HD-42s & ES-6.5s, and RSd 600.1 to Hertz EBX 202R. Audiocontrol Matrix w/ Kicker KISL line/RCA adapters. 4AWG power and ground wires w/ Rockford Fosgate RFDB1 disti blocks.