origamiguy has created a GUI tool to make your game MOD-ready (requires .NET 4.0 framework).   UNGTC UNGTC - ATD archive tool.   Download Link   Description:   This tool will extract and rearchive LEGO Racers 2 and Drome Racers archives (the Attention To Detail or ATD LEGO video games).   A while back, I started reverse engineering the LEGO Racers 2 and Drome Racers archive file formats (hence forth refered to as GTC). I figured out what almost everything was, but got stuck on the compression