Bro, this "buyer's remorse" is very common for me. When I was in the market for my F02, the news of the N54 HPFP was rampant in the market. California Bimmer drivers were contemplating a class action suit against BMW. Recalls were on the cards. Scared the daylights outta me, and I settled for the N52 F02. Regretted it the minute I put my signature on the line... Should have gone for the 740Li instead etc etc. Won't be so suay to happen to me etc etc. But now, a year of owning and driving my 730Li, I can't imagine myself not driving it. Love the linear pull and smooth lazy engine. I'm so glad to have landed the last of the N52B30n engines - car drives and wafts like a lazy Sunday afternoon dream.
Then, at the recent F13 launch, I was again tossing up between a 640i or 650i. In the end, after much contemplation (after all, I had a chance to sample both cars) I decided to go for the 640i and spec my options up. I thought the $45k saved would leave me plenty to play around with. Of course, the brothers on the forum know I then suffered another attack of buyer's remorse a couple of weeks into the purchase. After adding the M-sport, upgrading to 20" wheels, took out sunroof, put in factory tint, surround view, park assist, comfort seats, alcantara anthracite headliner (dun like the grey shit they were peddling), the 640i came up to be only about $15-20k cheaper than a stock 650i - so I kinda regretted not going for the monster V8 instead. Too bad, BMW Asia already firmed up my options and the car has already been slated for January 2012 production in Dingolfing.
I daresay, all the misgivings and remorse would soon be quickly forgotten though, when I finally take delivery of the F13 and start enjoying the manic 450Nm of pure, unadulterated torque available with the flexing of my right ankle, from 1300rpm. From gut feel, to butt feel, to heart feel - I reckon. I'll just end up loving the 640i every bit as much as I should.
If you've chosen the 640i cabriolet - go with your heart. Your first, primal instinct is hardly ever wrong - and the F12 is just every bit as fun a car to own and drive, as the F13.
Good luck and congrats again!