Well how bad is your coolant that you want to replace 100% of it? I would say that if replacing in normal intervals, which is every 105k together with timing belt and water pump, whatever comes out from the radiator and pump is enough.

 

It doesnt look too bad, just due for a preventive change.
My question is whether or not you can can get to the drain from the front wheel well as described for the gen 2 or do you need to go under the car.