M3 in a e60
 

I recently bought a 2006 530xi. Immediately after purchasing the serpentine belt snapped and wrapped around the crankshaft. Bits of the rubber belt went all through out the engine. Tiny shards through out the valves and oil intake probably down to the oil pan. So, motors done. It would take me to long to rebuild with my schedule and to costly for a shop to do it. So I want to know if I can fit a M3 engine in my 2006 530xi.

You may lose the "xdrive" part,...and have rear wheel drive only!!

Anything's possible. If it were mine, I'd look at a newer V8 to swap in. Lose the AWD and shred some rubber off tires instead of accessory belts.

How about putting a Honda V-Tech motor, light, in-expensive and high revving?

how does a shredded serpentine belt make its way into a sealed engine?

Through the crank seal.

I don't mean to offend by saying this, but if replacing a blown N52 is going to be too costly how in the world does an S65 swap make financial sense?!?!?!? What you are suggesting will be orders of magnitude more expensive and time consuming. Color me confused.

It's going to be 'costly' even if you replace with the same engine! Even if you get S65 at a great price,...it's still going to be costly,...as you will more than like need many things that aren't direct swap from N52 to S65,,....for instance,...is the tranny a direct mount to the engine? If you have to change out the tranny,...it's nearly guaranteed you will have to change out the tranny mount,...possibly the driveshaft as well. I suggest getting same engine,...make repairs,..and sell if you really want an S65! Or,...you most likely can upgrade to an N54 turbo setup! But now you're talking new DME,...etc.

Just replace with same engine and be done with it,.....as you will have to paid wayyyyyy more than you ever had in mind to convert to any other engine,...no matter what engine it is!

That sucks about the belt and it getting sucked into the crank seal - happens a lot.

IMO, a swap like that is best left to those with a lot of money to pay a shop to do it, or someone who's professionally-trained on cars and can do all the fabricating/troubleshooting themselves. Otherwise you will end up hating your life lol. :)

Seriously, the amount of stuff that won't work and you'll have to figure out - wiring harnesses, DME versions, compatibility of hardware and software, RWD, etc. - will seem endless.

I'd throw a used engine in it, and either continue to drive it or sell it.