I have the SN85g2v2. The lv2 is similar except no 1600 MHz HT bus, card reader or RAID. Other than that, it should perform roughly the same. They both use the nForce 3 150. The v3 uses the nForce 3 250.
I would probably research the 800 MHz vs. 1600 MHz HyperTransport. I don't see it making much of a difference since the memory interface is single-channel anyway. That's $76 bucks if you can live without RAID and the card reader.
Heat issues should be the same. I lapped my heatsink to improve performance a little bit. It uses a Sunon 80mm fan ( 42 CFM ), but you could replace it with a Thermaltake SmartFan2 ( 75 CFM ). I've done it with my other Shuttle systems but not with the SN85. Full load temps. ( Folding ) are around 57 C on an A64 3200+.