Not arguing just saying.
For WOLF to be 500lbs lighter than the R he'd have to have a 187 weight reduction from his (2door DSG) base factory weight of 3027.
I have a 2006 BMW 330 that I cut 200 lbs. of weight and retained all my interior. I achieved this with wheels, exhaust, brakes (yes, Stoptech BBK is lighter than stock), aftermarket seats (had I gone with race shells, I could have saved another 50lbs), carbon fiber hood, roof and trunk.
If Wolf has light weight wheels, they are most definitely the easiest way to drop about 40lbs. If he did a straight exhaust, pulled all the seats and did a light weight driver seat, he's more than likely already there or VERY close to the 187 lbs.
Body panels do add-up, but they don't make a huge difference. I dropped 40lbs. from my roof when I installed the CF roof, but that was only because I had a sunroof. If I didn't have a sunroof to start with, I would have only dropped about 20lbs. Hood was 18lbs, but the BMW hood is larger than the GTI, so I'm thinking it'll only be 15lbs. or less. You don't have the option to do a trunk, but mine saved 12lbs.
Getting rid of the entire interior and running a race shell for a seat will drop huge amounts of weight. You can get a race shell with mounting brackets and drop about 30lbs. That's a huge amount of weight. Stock seats weigh a ton due to the airbag and adjustments included in the seat. My BMW seats are leather with memory, lumbar all electric and they weigh 68lbs. each!
