I was struggling with pretty much the same dilemma. But, as some others have said, the choice is not really so extreme. When you consider that the 335 comes standard with adaptive zenons, folding rear seat, the alarm system and moonroof, the real difference in price is about $3000.
For me, I dropped Cold weather package and added heated front seats. I dropped the Driver's Assistance package and added PDC and rear camera. I deleted Driver's Assistance Plus, and dropped Automatic High Beams. This made up about 2/3 of the real three thousand dollar difference between the two cars. For me, getting the 335 was easily worth giving up those few things and adding a thousand bucks. I've still got Tech Package, Premium Package, HK, Rear Camera/PDC, Heated Fronts, and more. That's a very nice compromise I believe. To trim a little more I considered cutting the Tech Package and adding the Nav, but just couldn't do it!