I can't speak about the 530i vs. 540i comparisons other than go drive one and you'll know...
I do know that the 540i is amazing on the track. It might be heavy but it turns AND pulls in tons of cars on the straights with no issues.
I love my E39. It hauls the family, has plenty of power for DD duty, takes to the track like nobodies business and still schleps the kids around the day after. If only mine had the UAS to make dropping the car seats in a little quicker...
93 325is - sold!
2000 540ia- sold!