Absolutely true. Although I stick to the computer/physics end of electrical engineering I've seen the tolerances for the 12V bus and there is absolutely no way a motherboard will survive the spikes and voltage swings that automotive componenets are designed to withstand. Of course you can always try to design your own conditioner, but that will take more than just soldering knowledge. I would think for efficiency sake 300 watt inverter maybe a bit much, but a personal descision.