OP,
Ryan Amico (west coast) and David Aviles (east coast) have gotten the best feedback around here and both are very close to invoice pricing on a new M3. So it depends on your location and preference, and in your case, negotiating trade-in value.
I'm considering a new M3 this spring and will probably go through one of them. Unless a local dealer here in Cleveland is willing to match or do better, which is unlikely.
I believe it is too late to order a new M3 sedan, production ended in October.
If you're worried about the drive back to Indiana, just do performance center delivery. You get to beat on their M3, learn how to drive it, then take yours back home just in time for the 1200 mile service. Folks on here have posted pictures with their cars all wrapped up and protected just for the drive home, too. I'm strongly considering this myself, in addition to ED, to get the whole experience
As mentioned above, it may be worth your time to consider selling your 135 on your own - the return will probably be a lot better than a trade-in offer.
Hope that helps,
JM