Replacing those rubber Antennas with a Directional one

I have a Draft N adapter (rt2860 chipset Airlink101) I'm using in 'G' only mode to a Linksys two antennae Router.

Now the 'N' pci adapter has a three element loom and a three element Antenna cluster on one end.

What I was wondering is a twofold question:

A) Would I benefit from retaining all three antennas ( esp when I don't think I have any dual channel type equiptment) vs just going with a single (albeit directional) unit &

B) Might I somehow need to be wary of a different antennae burning out and/or drawing too much, not providing enough load, for the onboard radio?

For example;

2.4GHz-Range MP Series +8 dBi Panel Antenna MAXRAD 2.4GHz-range MP series panel antenna. Perfect for indoor/ outdoor Wi-Fi communications, or for any other form of microwave communications withing the 2.4GHz-range! This antenna provides a very precise directional control of your signal, with only 60-degree vertical/horizontal beamwidth. Perfect for pointing your signal to exactly where it needs to go! This antenna also features a +8dBi gain for ensuring you've got excellent signal strength!

Specifications:

• Frequency Range: 2.3 - 2.5 GHz * Gain: 8.5 dBi * VSWR: 15 dB * Dimensions: 5.1 x 4.7 x 1.5 -Inches (12.9 x 11.9 x 3.8 - CM) * Weight: 0.5Lbs (0.23kg) * Temperature Range: -40 to +70 Degrees Celcius * Cable: 3-Foot * Connector: Reverse Polarity SMA Male * Mount: MPAB11 Adjustable Azimuth/Elevation Wall-Mount

This antenna comes new in OEM packaging. Includes antenna, instruction sheet, mounting bracket, mounting instruction sheet, and hardware. ==============================================