On version 2 you can update the firmware on the ESC via a Usb adaptor. It has advance timing boost adjustment via the Esc which is not availible on Version 1. Probably slightly different feel from the power profiling. Also works with 1 cell batteries without needing a additional power source for the RX unlike version 1.
Either tc or non-tc would work with 2wd off-road buggy. Would be better to go for tc spec if you intended to run a 4wd at a later stage. Not sure if anyone is using the advance boost with a 2wd buggy so you might get away with version 1 and save yourself a few quid.
There is a setup guide/class recommendation guide for Lrp version 1 speedos.
http://www.lrp.cc/en/service/who-needs-what/?1=1&l=0