keep my car or get a mobility car?

ok so my mum can get me a mobility car at £150 a month am paying that just now for the insurance on my car a 1.2 corsa GOOD POINTS A BRAND NEW CAR!!!! any size engine free road tax break down cover free insurance free parts and labor if i want! swap it for another brand new car after 3 years BAD POINTS i wont get any no claim points :( but being a named driver on some ones car has to bring my insurance down a bit if in time i went for my own car ?? i will be paying £150 even after a year and that will never come down :( i cant do any mods like tint the windows add rims ect MY CARS GOOD POINTS its cheap to run its reliable parts are cheap i do all the work myself i can do any mods on it i want after a year it will be £80 a month to insure as i get my no claims points and will continue to drop each year BAD POINTS its a old car 2001 to be exact its a 1.2 thats it not many bad points on my car but i do like the temptation of being able to get a brand new bmw for £500 deposit and £150 a month lol and not need to worry about insurance or the car breaking or any thing else