[tony20009]

Well, between the two cars, I don't see too much difference other than that it'll be cheaper to keep your current car than it will to buy the M5, regardless of how many repairs you have to make. Of course, if you really think you'll be spending something like $30K or more in repairs over the next four years or so, perhaps the M5 is the way to go. I offer that because your stated basis for having the quandary is your concern about spending money to repair/maintain your 3er.

The M5 will have more power and a bit more interior space to be sure. It'll cost more to maintain and repair and it'll use more gas. Also, I wouldn't say they are perceived as better looking than the the E9x cars, but they look fine if the owner likes the look.

If I didn't have a very specific reason why I'd need to get the M5, and assuming I already own a 335i, I would just keep my 3er and save my money to buy something nicer and newer when the 3er really isn't worth keeping any longer. As I don't ever any more go to the track to drive, the only reason for my to get an E60-class M5 would be if I felt it'd be a collectible car someday and I was willing to keep it for a very long time.

Now, if you were asking about swapping for a 1M, I'd say go for it. That car will clearly have long term value and is a more special car than the M5.