And please try not to state the obvious on this board.......as you don't know quite who you may be talking to

There are comparisons........the M5 is somewhat of a finicky thorougbred and the 530i is more a well trained quarter horse.
The 530 is a well balanced, easy (with the auto) and fun to drive car, (with the manual) and the sport package .
It also has a lower cost of ownership and insurance plus it won't get you into trouble quite as easy as an M5 would .

He was asking for wisdom and alternatives.........so I gave him both.
It's his wallet so I don't know his fiscal pain tolerance (initially or subsequentlyt) so I gave him, what I view as, a sensible alternative to the M5.
YPYMAYTYC.....