Like I said, I wasn't aiming to add an interior. I thought I'd add the firewall beside the driver and didn't want to steal just a couple of parts from a Tamiya or Academy interior.
Then I decided that it would make sense to add the floor and it seemed as easy to cut a rectangle for the whole panel as it was just for the driver's compartment. Then it made sense to add the rear firewall... and then the fuel cells... and before I knew it I was making a full interior after all. When you think about it, the firewalls are just flat plates cut to shape.
The etched treadplate is Accurate Armour's 'single bar' treadplate. I had some in stock and that's what tipped the balance in terms of attempting to build the whole lot from scratch.
Those M577 pics of yours on Prime Portal are a brilliant resource. She's an old girl though. Not only does she have the early 'welded' hull extensons, but have you noticed the mismatched headlamp guards? Kerbside is the later flat plate style whilst the driver's side is the original round bar style.