Nearly $2k recently spent on new a/c compressor (318i), full detail, new rear Bridestone RE-11 tires.
If you lowball the parts here it is:
$10k motor
$2k T56/clutch/flywheel
$1.5k Holley EFI/harness/sensors
$1.5k rims/tires
$2k Samberg mounting kit/headers
$2k custom intake/radiator/splitter
$2k stoptech BBK
$2k suspension
$1k interior
$1k built diff/dshaft
That's $25k easily.
Then add in a car, $10k paint/welding on flares, all labor to do the swap, running around for parts/dropping off car for work, tuning, sorting, etc.
It's at $30k obo