an M3 is going to run you 15k anyway you look at it. If you buy one for less, its going to need whatever the difference in price is put into it.
Not only that, but they are a bitch to maintain, you need to get the valves adjusted every 5-10k (i forget the actual intervals, but they are short), the motors blow all the time because they are basically a race motor.
Seriously the M3 would never make a good daily.
Don’t get me wrong, I LOVE this car, but I could never build one with the stock s14.