Someone knock some sense into me!

[petrolhead]

We're currently running an 03 Nissan X-Trail sport diesel as a cheap beater while we work on the old dave ramsey baby step 6, and its been fantastic,in 20k miles its had a window switch, a door handle and a pair of track rod ends. It drives like a new car, it does 33mpg city and i've seen 40mpg streching its legs sitting at 70 travelling to manchester with its 6 speed manual.
So why do I find myself still yearning for the endless wallet emptying soul destroying world of hurt that is big bmw ownership? I've had an e30, an e36, an e23, 2 e32s, 2 e38s, an e39 and an e60 and other than the 3 series car each one was an ever increasing moneypit that caused hours of swearing and skint knuckles and trips to the parts shop or breakers yard so why do I still want to chop the old faithful nissan in for an e53?
Tell me I should do my family a favour and get this nonsense out my head and run this old girl til the wheels come off then get a diesel pathfinder or something.
Please? Everytime I see an e53 I want one bad, in black on black, 3.0d sport with the heated seats and decat and remap.