Need Advice on CD Changer Install Kit 2003 325i

[atwnsw]

Okay, so I have decided to install the Alpine CHA-S634 CD changer in my car (2003 325i). I am totally inept when it comes to mechanical projects but I am optimistic that I can tackle this one. I have read numerous DIY instructions and will tackle this project AFTER I have all my correct parts and tools.

I have ordered the following parts:

Alpine Ai-Net to M-Bus Adapter
Soundgate Adapter
CHA-S634 (about to place order)

I don't need the trunk liner as my car came with the premium package and has the CD liner for CD changer already installed.

THE BIG QUESTION:

Do I need to order BMW CD Changer Install kit (Part # 82-11-1-470-436) which is about $50?

The car currently has two plastic trays inside the CD changer space. I was going to remove the liner but it is a bit complicated and I only want to do this once.

Can somebody with 100% confidence tell me if I need this part to do the install myself?

Thanks

Anthony