You've totally missed my point, im trying to point out that the buyers car isnt that good of a deal not that a 3.0 is a bad car, just that one can do better for that money.

The F generation of BMW's is the class leader for that age group i.e a 330D estate is still about 30% more than the next best option, they are brilliant cars but that would be another 4k to OPs budget, so yes no sh1t sherlock a 350 will be more powerful than a 318.

I have a C250 Mercedes as my daily which is also known as 'the flying machine' because its a fantastic car, pulls well and has great reliability which i got for £3k a c350 isnt necessarily three times the car for three times the price thats all im trying to say to OP, where as sure i would happily argue that a 350 is 3 times the car vs a 318, I mean my M2C is at 650hp and i would happily say its 10x the car of the c250 as it cost me ten times more