Both those boards only have the regular MCP, at least that's what the detailed specs say.
MCP boards lack the APU (or it's disabled at the hardware level) and therefore are totally reliant on the ACI/AC'97 CODEC for audio resulting in lower performance and quality due to all the effects processing being done in software. MCP-T boards have an AC'97 CODEC (and for some bizarre reason let you use it in place of the APU if you install the CODEC drivers) as well but since the effects processing is done entirely in hardware (like any other sound card) it's light years ahead of CODEC-only solutions.
SoundStorm is really just nVidia marketing BS. It refers to nForce2 boards that have an MCP-T South Bridge (and therefore the APU), enough analog outputs for discrete 5.1 channel output without having to double up and at least SPDIF digital out to utilise the integrated Dolby Digital encoder. With the exception of the Chaintech 7NJS (which forgoes the APU entirely for a C-Media sound chip), any nForce2 board with an MCP-T is technically SoundStorm capable but unless it meets nVidia's requirements it isn't allowed to advertise this fact. The 8RDA+ is like that, it has an MCP-T (it's probably one of the cheapest boards that does) but since it doubles up the Line-In and Mic-In connectors and doesn't include an SPDIF header in the box (EPoX do sell it seperately though), it isn't allowed to carry the SoundStorm tag.
The LAN is somewhat similar to the audio in that the nForce2 chipset only provides the MAC half in hardware, it still needs another chip, called a PHY (short for Physical Layer Transceiver I believe), before it can be useful for anything. Most other boards just use a PHY on it's own (which is the purpose the chips are sold for) and emulate the MAC in software (which again the nForce2 chipset allows for if you install the PHY drivers) which reduces overall performance.
That Gigabyte board looks interesting, it seems to have disabled the onboard nVidia MAC and used a straight RealTek (probably PCI whereas the nVidia MAC connects via HyperTransport, not that it really makes all that much difference at 10/100 speeds) LAN chip which is probably inferior to the onboard nVidia MAC. I certainly wouldn't recommend that board, even if it had an MCP-T.