Operating Temperature it can support up to 70deg (by design) but the unit is only tested at 25 deg ambient. The unit is not intended to work for the automotive temperature range.We recommend using a single coax cable, if you want to increase the length then you can use any coax cable with higher bandwidth (few GHz), low loss, 50-ohm cable but it may impact the data rate (degradation of the rise time of the signal). Please note we have not characterized the unit with other cable lengths.