Originally Posted by Prince_of_Persia
If you have a tight budget of $30K, you should not buy any of these cars IMO.
Get a Subaru STI. I got mine used, only 600 miles (engine not even broken in) for $30k. AWD, seats 4 comfortably, hatch for storage. I was getting 19mpg with very spirited driving. The stock stereo sucks, so just get the Subaru subwoofer installed at the dealership.
Edit: My STI was faster than my 335i and sounded more badass. Stock.
I would not get a used M3 or C63 for $30k. That car is gonna be beat to sh*t.
I've never even seen a M5/M6 for $30k.
Just my 2 cents. I have no experience with a used a M3, but I do spend a lot of downtime perusing this forum and "window shopping" on cars.com.