Aral petrol station in Adenau sells 102 ron and is good stuff.
Shell in Cochem sells VPowerRacing (100 ron) as Shane says.
I'd take a single bottle of NF as i think you only use half per tank, only needed in Belgium if you're mapped for 99 ron fuel as the VPower there is only 98. If you're still on a standard map you won't need any octane booster.
On the autobahns we tend to cruise at 80ish with the occasional blat slightly above that
