I have the older time capsule a1355 model if I buy a new version will I see a big difference in my wifi speed and range? Thx.
likely if the device does 802.11AC likely if the device does both bands (2.4Ghz and 5Ghz) if the device does not do AC, time for a newer device that does http://www.apple.com/airport-extreme/
The new models do offer even a modest benefit in wireless N performance, but you most likely would only see a real world increase in range with the new model over the old one.