I have an 04 M3 SMG. Within 6 years of driving it, I changed my cats 2 or 3 times, alternator once, and LSD Left seal twice. There's one belt I changed, I forgot what it was... too long ago.
(These cost about 12,000CDN to replace under warranty).
The Cats alone were 6,000CDN...
After my aircare is done, I will not replace my cats if they fail on me again.
Do oil change at every 4500miles. Do spark plugs at every 40,000miles.
I did my 1st brake job at around 30,000miles. Now, I have around 65,000miles. I've done two brake jobs in total. Get CoolCarbon brake pads from EAS for lot less brake dust. OEM Brake pads are horrible for brake dust.