Aftermarket Antennas

Anyone purchased any higher dBi antennas before? I currently run 2 - DIR-655 as AP's only, one on either end of the house. Trying to eliminate one of them with the following antennas. Using SSIDER it seems the one with stock antennas gives me better distance. Anything need to be changed to accommodate the larger antennas? The two were sitting side by side, one channel 1, other on channel 6 when testing.

Further testing, moved access point to top of cabinet in middle of house on the main floor and coverage has greatly improved. Gonna be hard to get cat6 to there, though. Will these antennas only benefit with the device up high?

Here's the main AP with the upgraded antennas. It sits in a floor joist between the basement and main floor. Like I said, moved this to main floor, top of the cabinets which is highest spot in the house and coverage greatly improved. Any suggestions greatly appreciated.

Anyone? The antennas I bought are a 6dBi instead of the stock 3dBi. Wasn't going too big, just wanted to see an improvement.