730 E66 is a very straight forward car in terms of mechanical.
electrical demons can be a headache if there is anything electronically not working in the car. look for sign of wear and tear on the buttons and knobs. this will give you tale tale signs of wether it is taken care or not in the past. any electrical function such as seats, heater, entertainment, navigation or display not working is something that can cause serious headache.
the engine, i believe is a straight 6 magnesium block which is pretty common in the bmw range and parts are readily available and not too exhorbitant.
in the past, suspension can be taboo to talk about as the self levelling system and air suspension is state of the art and not many peopel understand how it works and "bloody expensive" to repair. now, its a walk in the park and it is 5K thingy rather than 30K thingy.
road tax for 3 litre , ard 2K. insurance is up to you how much you want to insure it and what kind of insurance. bro.. honestly this kind of question gave it away telling me you are a novice. kekekekeke. never ask this in a car workshop.. nanti kena sembelih. do google some of this knowledge. you will find it very very useful in the future.
fuel consumption should be around 12-15L/100km mix drive. highway around 10-11.
do insist to look under the car when inspecting as most engines and interior exterior are cleaned for display but not the undercarriage. look for any signs of wet oil and dents and major scratches. can be sign of abuse and failing oil sump gasket, leaky gearbox, leaky suspension and whole lot more. do this for every use car that you are gonna buy. not just bmw
if you are a car enthusiast, then google more on the e66 and 7 series forum, you will find that the enthusiast know how to maintain the car better than workshop. for any signs , do some research and most of the time you will know what wrong and when go to any decent workshop who are familiar with continental cars. they can do the job. otherwise i will recommend you to get a basic DIAGNOSTIC SCANNER and reset tool.
price wise, cant commend. 85-100K would be my price depending on condition. btw.. just tires, you will be looking at 5K all round, so its not for the faint hearted.
