Each of these Intel® products that you've mentioned are destined to different types of access to a network. One is wired and the other one is wireless and it is up to you to decide which one will be better for you depending on the intended usage.
Regarding the Intel® 82577LM Gigabit Network Connection, we recommend that you contact this forum for detailed information:
Regarding the Intel® Centrino® Ultimate-N 6300, Dual Band, you can find its information by accessing this link: http://ark.intel.com/products/59474/Intel-Centrino-Ultimate-N-6300-Dual-Band Intel® Centrino® Ultimate-N 6300, Dual Band Specifications
*Please bear in mind that Intel does support integration as all Intel® Wireless Adapters are meant to be installed by the OEM and not meant to be sold to end-users. For further information on this matter, please access this link: http://www.intel.com/content/www/us/en/support/network-and-i-o/wireless-networking/000005687.html?wa... Regulatory Information Regarding Hardware Installation or Upgrade