I don't know how Canada works, but here in MA, you'd be looking at $3500/mo after taxes assuming you claim 0 allowances on your W4 (since you're 22 you wouldn't need to pay for health insurance here either - you can stay on your parents plan).
Let's say you pay $1000/mo for your M3. That still leaves you plenty of money for insurance and gas. You'll get a 50,000 mile warranty and free oil changes and brake jobs from BMW so the expensive repairs argument is moot. Assuming you don't go clubbing every weekend, you'll still be able to put away money every month into savings.
$60k for a 22 year old is a respectable salary. The only kids I knew getting that out of school were BSEE or Finance/Accounting majors, so kuddos to you.
Unless you work for an unstable company or that $60k is commission, I say do it.
PS: If you're smooth talker you won't have to worry about bringing girls back to mom's crib; they will invite you back to their's