[Rei]

Topping off is just fine. I just want to provide a fair warning on draining the system. To do a proper drain and refill is a very annoying process involving tilting the car at an angle running the motor and lots of burping. Every time I do it on any MR car be it the Lotus or the MR2 I hate it. Hence why I switched to Evan's Coolant. That was a huge PITA doing a full bleed. Air tools are your friend for that process.