You need to blank in the rear windows for sure... but I'd wrap them the same colour as the paint rather than tint them, so that they looks like a van rather than just a 500 with tinted windows.
Removing the rear seats and putting in a flat tray panel is good... but I'd also look at bolting in some kind of plywood bulkhead and sides, so that you can actually use the "van" as a van.
You could tie the bulkhead to the flat tray panel, the sides and possibly the front seat belt anchor points so that it's all rigid. If you have tinted windows, the side panels could go up to the roof.. although the shape of the 500's upper sides might mean it's easier to just fit side boards up to the window line/the height of the front seats.
The bulkhead should at least be the height of the front seat backs, so you don't get clobbered by parcels or bits of gearbox, etc. depending what you're going to use the beast for. It might be worth fixing some kind of grill or net to the top of the bulkhead to stop things flying over the top of the bulkhead and to make it look more like a van.
And you neeed to fit roof bars (yes you do) for a more authentic look.
If you're not going to use it as a van, then it is also obligatory to fit a massive sound system and line the back in purple velour. You know I'm right..
Ralf S.
