Hi guys, my first post so please be gentle

Right I will be ordering a Mk7 GTI by the end of the week and I'm after some advice on options and haggle room.
The options that are a must have for me are:
Keyless
Rear camera
Pure white
The options I'm not sure whether to get are:
Discover nav
Dynaudio
Reflex silver
Keyless and rear camera are cheap little options that I believe will keep me entertained. My current car (audi a3) has Bose which is very good, I'm not sure how good the standard system is in the GTI but do you guys think an upgrade in audio is worth it?
Nav is something that I think would make life easier not necessarily better as I have a TomTom live which I must say is awesome, I don't really use the nav as I tend to know where I'm going but would be more convenient on those long trips.
If there's any options you guys believe as a "must have" please but it forward as I'm all for toys.
Now last time I purchased a car new in all the excitement I forgot to haggle, I've had quotes from car wow and they have come back at roughly 24k with pure white keyless and rear view, the problem I have is will they take that discount off my part ex?
If you guys don't mind I wouldn't mind knowing what you guys paid for your GTI's including extras, at least then I'll have something to aim for.
Thanks in advance
Cheers