Well dont forget ultimately this is your car and i assume you'll be driving it for a few years so you may as well get the options you want, not what others think are useless. Heres my 2c

The only two i would cross off it Detroits and RNS510 and as mentioned you may not be able to buy the Detroits for as cheap but there are plenty of other wheels which look as good if not better than them. RNS510 you can ebay but you will need someone to change CANBUS codes. You can then sell your RCD510 for $300-500.

About the xenons, i want them but for the price they arent for me. You might feel differently but im young and can see well in the dark

PS: With all those options listed you are getting close to golf R money too.