2005 X-type 3.0 V6 sedan - premium sound

Hi guys. I've read in other thread(s) about the importance of an aftermarket stereo and the depth of it because of issues fitting it. I've tried searching for more details on the forums but couldn't find any. Does anyone have any information for me about the suggested maximum depth in inches? Right now I'm looking at about 6.5" but I want to get an idea for around what I should go for. Thanks for the help!

EDIT: Thanks to the "Related Topics" after posting this thread, I found the answers I needed. For some reason the search function doesn't seem as efficient. I'll post the related threads below. Feel free to add on if you want!
https://www.jaguarforums.com/forum/x...x-type-161259/
https://www.jaguarforums.com/forum/x...s-info-102632/

 

So I'm just about finished with the new stereo and I noticed something on the wiring instructions. It says "Important - Splice these wires in the factory harness to receiver ground or to the vehicle chassis to prevent triggering the factory alarm system:" Then it describes to use the red wire for X-Types.

I haven't tried to hook it up yet, I'd like to avoid an annoying alarm situation happening if possible. I was hoping for some more details about this splicing.

Please forgive my ignorance (this is the first time I've ever even worked with wiring), but does it want me to cut the red wire from this and splice it with a ground?



I've found nothing specifically about this using the search function. The only other thread I've found that shows a close up picture of their own stereo hooked into this receiver doesn't look like he messed with the factory wires at all. Please advise!