The GAE, which weighs approximately 40 lbs., has Isoacoustic GAIA III feet, rated for up to 70 lbs. The HW-40, which weighs approximately 70 lbs., has Isoacoustic GAIA II feet, rated for up to 120 lbs. FWIW, I asked Isoacoustic Technical Support for their recommendation in choosing these feet for both TT's. I also use their feet under my speakers.
The feet improved the clarity of the sound, both turntables are quieter and bass is noticeably better controlled.
Yes the Gimble Tone Arm is available for other VPI turntables as well. This is a very nice sounding tonearm and is the main reason why the HW-40 sounds as good as it does. In other respects including speed accuracy, quietness and so on, the two turntables are very similar.