hi! ok so i bought the dlink antennas for $10 each (newegg refurbished product).
it barely increased the signal. BUT it made it more stable if that makes sense. For example, the regular stock antennas go from very good to excellent and then back to very good, etc. With these high gain antennas, they stay at excellent. Sometimes it drops to very good but then goes back to excellent.
I had another set of high gain antennas from radioshack. They are meant for the old linksys TNC routers, but i just bought the TNC to SMA adapter. I must say the radioshack ones are a little better. The dlink antennas IMO has to be positioned correctly as if its somewhat like a directional antenna, wereas the radioshack antennas are more like "place it where you want" type of position.
In my view, i feel that the dlink antennas are more of a narrow-er doughnut shaped beam while the radioshack has more of a wider doughnut shaped (hopefully that makes sense)
all in all, if you want to increase distance, a bridge will work. (dd-wrt is another possibility but it has to be compatible). OR if you ever plan on getting antennas, dont expect a longer distance, but expect a more consistant connection.
^_^