Garmin Forerunner 205 VS. 305 and garmin 405. these three gamin gps models have differenct funtions. The 205 and 305 have been out longer. Compared to the 205, the 305 adds a heart monitor, and is also compatible with an optional foot pod (for indoor use) and cadence sensor (for bicycling). If you shop right this time of year, you can actually find the higher end 305 for the same price or cheaper than the 205, since it’s the most popular model and has been for awhile. You can’t add …