My guess is being set at 13.5V it doesn't have a ntc thermistor so no accomadation for hot or cold ambient/battery temperature like OEM-street regulators. 13.5V is on the lower end of the charging range with the norm being 13.2V-14.8V. A shorter battery life may also be the result. I would also suspect the non-variable charging point may be counter to optimum emissions requirements via torque load hence "Drag Race Only". But this is all speculation. RUN IT.