1. No regrets whatsoever. If I had to order my car again, I'd buy the EXACT same spec.
2. I went with black leather and brushed aluminum trim. Aluminum may be considered by some to be old or last decade, but I think it provides excellent contrast with a black interior. I don't think I'll get tired of it anytime soon, at least not as long as I have a car like the M3. If I were getting a more luxurious car (or even if I were getting this car) and I wanted something a bit less flashy, I'd probably switch to Deep Sea Blue or (even better) Tanzanite Blue. But on the "Classy vs. Sporty" spectrum, Le Mans is definitely closer to Sporty, but not too far off the midpoint so there's plenty of class to be had. Pics of my car here: http://www.m3post.com/forums/showpos...73&postcount=1
3. Haven't had any problems caring for it at all.
4. I get compliments on the color CONSTANTLY, from people of both genders, all age groups, and all levels of car enthusiasm. People have walked out of their way to come over to my car and tell me how much they like the color, sometimes even saying that they like this particular shade of blue as opposed to just liking blue cars -- and that includes BMW enthusiasts who can tell it apart from Interlagos (aka "blurple").
As for people saying to get Interlagos because Le Mans is available on non-M cars, don't worry about that. First of all, it's only available with the M Sport package, which itself hasn't been available for very long. But I see lots and lots of BMWs every day (including at CCA meets) and in the 1.5 years I've had my car, I've only seen TWO other Le Mans BMWs, one M3 and one 335i. Every other time I've seen a blue BMW model that Le Mans is/was available on, the blue actually on that car has been either Interlagos or Montego.
Bottom line: MW is a great color too and probably one of the more interesting whites I've seen -- but it's still boring and common white. Le Mans definitely has some pop, so if you just want an attractive yet stealthy color, MW may be for you. But if you want something that will stand out somewhat but not enough to be gaudy, get LMB. When it's clean and out in the sun...
Check out the first couple pages of the official Le Mans thread if you need any further convincing: http://www.m3post.com/forums/showthread.php?t=182199