Assuming you also have a password set on the router itself, that plus the WPA2/AES wireless encryption setting (with a strong key) means that you have the security well covered.
...I see a maximum 130Mbps although frequently lower (as shown in Windows connection status display)
300MBps requires a router capable of at least 2x2:2 (2 transmit antennas, 2 receive antennas, 2 spatial streams) operation plus the use of channel bonding (combining two 20MHz channels), which is not recommended since it can cause interference problems and actually reduce overall performance
When using an access point with a 3x3:2 configuration (like the D-Link DIR-655) the best one can achieve without using channel bonding but with a short GI (Guard Interval) is 144.4MBps. Of course the real world throughput will be less than that.
The Intel 5100 supports 3x3:2 on receive, but only 3x3:1 on transmit, which means that without using channel bonding and with a short GI the best it can achieve is 144.4MBps on recieve and 72.2MBps on transmit. Those would be further limited to 130MBps and 65MBps respectively if using the default (longer) Guard Interval.
Bottom line: For maximum overall performance I recommend setting 20MHz (standard) channel width combined with a short GI. To do this, on the access point (router) under Wireless Network Settings, set the Channel Width to 20MHz. Then under Advanced Wireless Settings, place a check mark to enable Short GI.
On the adapter side I recommend leaving all settings to default except for Power Management, which I recommend manually setting to "Highest" (maximum performance, maximum power consumption).
In my experience these settings will allow for the best overall performance under most conditions, both locally and when you are a guest on another network. Scott.