As others have mentioned it depends on how long you plan to keep the car.
The problem is, the IS300h attracts quite a specialist buyer. They're not your average buyer and hence, most do buy from a Lexus approved scheme or will atleast make sure it has a full Lexus service history.
At the end of the day, its a Premium car with premium servicing. I guess you could also put budget tyres on but buyers will notice this straight away. I wouldn't buy a premium vehicle with budget tyres, same with servicing.