Welcome along Joel. If you get your questionnaire back to Tim and get full access to the site there is a lot of information regarding upgrades to the Hi Line system. Most replacement units come from Sean (aka Radioguy) on the 75/ZT OC forum here:
What car have you got? What are the last three digits of your VIN? Any photos?
Nich.
Nicholas John Peter Tinker - # 484
Manufactured on Tuesday 27th April 2004 @ 12.17.47.
Commission Number: 24468.
Brochure Model: M3 Tourer 4.6 V8 260PS.
Specification Code: L01B.
CICode: D1511.
Trim Level: TL8.9 (M3).
65th ZT-T 260SE to be made out of 115.
11th ZT-T 260 SE in Pearl Black (PBT) out of 23 produced. Manufactured in the UK by MG Rover Group Ltd.