Affordable to own a 260k car , at least 6k disposable income monthly. Thats estimation is based on stretching the loan to maximum tenure with 10% dp and caculate in maintenance plus yearly insurance and roadtax.
I only consider car within my allocated disposable income every month.
No point looking at gross or nett because each people have different expense and commitment so just deduct everything out and how much your disposable determine your affordability to own that 260k car.
So i would say 6k is the minimum you will need in order to enjoy the car without worrying about the maintenance and some other unexpected repair.