Personally I'd just have the computers setup side by side record 1-8 on the first computer, and the additional tracks recorded to the other computer, no sync cables. Just make sure the format is setup the same (24 bit 44k) on both. Hit record on one machine and then record on the other.
Have the drummer strike a snare hit or something to give a reference point across all of the tracks to be recorded. Click the song off and away you go.
Once the recording is done, just copy the wave files from computer #2 onto a flash drive or cd and import it into the first computer's song file.
Use the snare hit that is across all tracks to line all of the files up. Ez Peezy.
If you are woried about the TOS then just download and install reaper on the second computer. (Of course pay for it if you continue to use it)
Or better yet, you could purchase a scaled down version of X2 (Music creator) to record the additional tracks.