T-Rex Vulture Distortion Pedal

The T-Rex Vulture started its life, when Michael plugged in one of the very first pedals we made. That pedal had a certain sound to it that we really liked, but it was a bit grungy in the low-end. We wanted to make a pedal with that sound, but with a tighter, less fuzzy low end and with more gain.
We opened up the pedal and painstakingly measured everything in it, to find out why it sounded so good, and found a couple of resistors that would be better with other values.

Was it modified earlier in life or was this just a very good sounding mistake from when it was made in Lars´ basement way back in the 90´s?
All we know is that the basic sound was cool and we left it at that, and went on to focus on getting the low-end tight – but BIG!
The fruit of our labor is a pedal that has a great, throaty distortion with a nice bite to it but the low end and low midrange can be shaped in many ways, thanks to the low- and fat-boost knobs. This allows the player to dial in almost stupid amounts of lows, but the distortion stays tight, not muddy.