Gearhead (and Rogue, incidentally) is one of the few games that seem much easier to get up and going on Linux systems than Windows. I just install it through the precompiled deb-files already bundled with my OS. As for Gearhead 1 vs. 2, I'd say the first game is more finished, and offers more versatile fun. In GH 2, you more or less have to become a mecha pilot (in GH 1, you can just ignore mechas altogether and become a professional rat catcher or something), and the game is still under (passive) development. The UI is smoother in GH 2, though, and it does feature the randomized plot thingies, which for me is a big part of the games' appeal.
As always,
Minotauros