Unless you know what you're doing, avoid such cars like the plague! I've worked for an insurance company in the past and you'd be surprised what can be repaired. If an insurer feels fit to write a car off, then there's a damn good reason. Saying that, any type of flood damage immediately writes off most, if not all cars. You don't know what nasties were in the water - sewerage, animal excrement from field run off etc. Even if the car only had 6 inches of water inside, it will have got into all the fabrics, carpets, plastic panels behind the dash which even with the best valeting, will return as nasty niffs and pongs that will be impossible to remove. So far you see the problem. You have a car that is a potential health hazard with all the gunk from the flood water soaked into the seat fabric and carpets and a car that will potentially stink to high heaven if left parked in the sun in summer. That's before we get on to the potential of damage inside the exhaust, the catalyst, bearings on the outside of the engine. Then you don't know how deep the flood was? All the above is on 1 foot of flood water (6 inches inside). If it were a 3 foot flash flood with the car was bobbing around in a car park for a few days, then the problems are even worse. You don't know how bad the flooding was. You only have their word it was minor and as you've seen above, even minor flood damage can cause all sorts of future problems. Personally I'd walk on by and avoid this car. As others have said above too, the warranty is invalidated if the car is written off. You will also have to tell all future insurance companies and some (not all) will restrict cover to third party only and others may restrict the value of what they'd pay out in future claims to reflect it's already significantly lower value.